draft-ietf-keyprov-dskpp-14.txt   rfc6063.txt 
KEYPROV Working Group A. Doherty Internet Engineering Task Force (IETF) A. Doherty
Internet-Draft RSA, The Security Division of EMC Request for Comments: 6063 RSA, The Security Division of EMC
Intended status: Standards Track M. Pei Category: Standards Track M. Pei
Expires: March 11, 2011 VeriSign, Inc. ISSN: 2070-1721 VeriSign, Inc.
S. Machani S. Machani
Diversinet Corp. Diversinet Corp.
M. Nystrom M. Nystrom
Microsoft Corp. Microsoft Corp.
September 7, 2010 December 2010
Dynamic Symmetric Key Provisioning Protocol (DSKPP) Dynamic Symmetric Key Provisioning Protocol (DSKPP)
draft-ietf-keyprov-dskpp-14.txt
Abstract Abstract
DSKPP is a client-server protocol for initialization (and The Dynamic Symmetric Key Provisioning Protocol (DSKPP) is a client-
configuration) of symmetric keys to locally and remotely accessible server protocol for initialization (and configuration) of symmetric
cryptographic modules. The protocol can be run with or without keys to locally and remotely accessible cryptographic modules. The
private-key capabilities in the cryptographic modules, and with or protocol can be run with or without private key capabilities in the
without an established public-key infrastructure. cryptographic modules and with or without an established public key
infrastructure.
Two variations of the protocol support multiple usage scenarios. Two variations of the protocol support multiple usage scenarios.
With the four-pass variant, keys are mutually generated by the With the four-pass variant, keys are mutually generated by the
provisioning server and cryptographic module; provisioned keys are provisioning server and cryptographic module; provisioned keys are
not transferred over-the-wire or over-the-air. The two-pass variant not transferred over-the-wire or over-the-air. The two-pass variant
enables secure and efficient download and installation of pre- enables secure and efficient download and installation of pre-
generated symmetric keys to a cryptographic module. generated symmetric keys to a cryptographic module.
Status of this Memo Status of This Memo
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http://www.rfc-editor.org/info/rfc6063.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 6 1. Introduction ....................................................6
1.1. Key Words . . . . . . . . . . . . . . . . . . . . . . . . 6 1.1. Key Words ..................................................6
1.2. Version Support . . . . . . . . . . . . . . . . . . . . . 6 1.2. Version Support ............................................6
1.3. Namespace Identifiers . . . . . . . . . . . . . . . . . . 7 1.3. Namespace Identifiers ......................................7
1.3.1. Defined Identifiers . . . . . . . . . . . . . . . . . 7 1.3.1. Defined Identifiers .................................7
1.3.2. Identifiers Defined in Related Specifications . . . . 7 1.3.2. Identifiers Defined in Related Specifications .......7
1.3.3. Referenced Identifiers . . . . . . . . . . . . . . . 7 1.3.3. Referenced Identifiers ..............................8
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 8 2. Terminology .....................................................8
2.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . 8 2.1. Definitions ................................................8
2.2. Notation . . . . . . . . . . . . . . . . . . . . . . . . 10 2.2. Notation ..................................................10
2.3. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 11 2.3. Abbreviations .............................................11
3. DSKPP Overview . . . . . . . . . . . . . . . . . . . . . . . 11 3. DSKPP Overview .................................................11
3.1. Protocol Entities . . . . . . . . . . . . . . . . . . . . 11 3.1. Protocol Entities .........................................12
3.2. Basic DSKPP Exchange . . . . . . . . . . . . . . . . . . 12 3.2. Basic DSKPP Exchange ......................................12
3.2.1. User Authentication . . . . . . . . . . . . . . . . . 12 3.2.1. User Authentication ................................12
3.2.2. Protocol Initiated by the DSKPP Client . . . . . . . 13 3.2.2. Protocol Initiated by the DSKPP Client .............14
3.2.3. Protocol Triggered by the DSKPP Server . . . . . . . 15 3.2.3. Protocol Triggered by the DSKPP Server .............16
3.2.4. Variants . . . . . . . . . . . . . . . . . . . . . . 16 3.2.4. Variants ...........................................17
3.3. Status Codes . . . . . . . . . . . . . . . . . . . . . . 17 3.2.4.1. Criteria for Using the Four-Pass Variant ..17
3.4. Basic Constructs . . . . . . . . . . . . . . . . . . . . 18 3.2.4.2. Criteria for Using the Two-Pass Variant ...18
3.4.1. User Authentication Data, AD . . . . . . . . . . . . 19 3.3. Status Codes ..............................................18
3.4.2. The DSKPP One-Way Pseudorandom Function, DSKPP-PRF . 23 3.4. Basic Constructs ..........................................20
3.4.3. The DSKPP Message Hash Algorithm . . . . . . . . . . 23 3.4.1. User Authentication Data (AD) ......................20
4. Four-Pass Protocol Usage . . . . . . . . . . . . . . . . . . 24 3.4.1.1. Authentication Code Format ................20
4.1. The Key Agreement Mechanism . . . . . . . . . . . . . . . 24 3.4.1.2. User Authentication Data Calculation ......23
4.1.1. Data Flow . . . . . . . . . . . . . . . . . . . . . . 24 3.4.2. The DSKPP One-Way Pseudorandom Function,
4.1.2. Computation . . . . . . . . . . . . . . . . . . . . . 26 DSKPP-PRF ..........................................24
4.2. Message Flow . . . . . . . . . . . . . . . . . . . . . . 27 3.4.3. The DSKPP Message Hash Algorithm ...................24
4.2.1. KeyProvTrigger . . . . . . . . . . . . . . . . . . . 27 4. Four-Pass Protocol Usage .......................................25
4.2.2. KeyProvClientHello . . . . . . . . . . . . . . . . . 28 4.1. The Key Agreement Mechanism ...............................25
4.2.3. KeyProvServerHello . . . . . . . . . . . . . . . . . 29 4.1.1. Data Flow ..........................................25
4.2.4. KeyProvClientNonce . . . . . . . . . . . . . . . . . 31 4.1.2. Computation ........................................27
4.2.5. KeyProvServerFinished . . . . . . . . . . . . . . . . 33 4.2. Message Flow ..............................................28
5. Two-Pass Protocol Usage . . . . . . . . . . . . . . . . . . . 34 4.2.1. KeyProvTrigger .....................................28
5.1. Key Protection Methods . . . . . . . . . . . . . . . . . 35 4.2.2. KeyProvClientHello .................................29
5.1.1. Key Transport . . . . . . . . . . . . . . . . . . . . 35 4.2.3. KeyProvServerHello .................................30
5.1.2. Key Wrap . . . . . . . . . . . . . . . . . . . . . . 35 4.2.4. KeyProvClientNonce .................................32
5.1.3. Passphrase-Based Key Wrap . . . . . . . . . . . . . . 36 4.2.5. KeyProvServerFinished ..............................34
5.2. Message Flow . . . . . . . . . . . . . . . . . . . . . . 37 5. Two-Pass Protocol Usage ........................................35
5.2.1. KeyProvTrigger . . . . . . . . . . . . . . . . . . . 37 5.1. Key Protection Methods ....................................36
5.2.2. KeyProvClientHello . . . . . . . . . . . . . . . . . 37 5.1.1. Key Transport ......................................36
5.2.3. KeyProvServerFinished . . . . . . . . . . . . . . . . 42 5.1.2. Key Wrap ...........................................37
6. Protocol Extensions . . . . . . . . . . . . . . . . . . . . . 43 5.1.3. Passphrase-Based Key Wrap ..........................37
6.1. The ClientInfoType Extension . . . . . . . . . . . . . . 44 5.2. Message Flow ..............................................38
6.2. The ServerInfoType Extension . . . . . . . . . . . . . . 44 5.2.1. KeyProvTrigger .....................................38
7. Protocol Bindings . . . . . . . . . . . . . . . . . . . . . . 44 5.2.2. KeyProvClientHello .................................39
7.1. General Requirements . . . . . . . . . . . . . . . . . . 44 5.2.3. KeyProvServerFinished ..............................43
7.2. HTTP/1.1 Binding for DSKPP . . . . . . . . . . . . . . . 44 6. Protocol Extensions ............................................44
7.2.1. Identification of DSKPP Messages . . . . . . . . . . 45 6.1. The ClientInfoType Extension ..............................45
7.2.2. HTTP Headers . . . . . . . . . . . . . . . . . . . . 45 6.2. The ServerInfoType Extension ..............................45
7.2.3. HTTP Operations . . . . . . . . . . . . . . . . . . . 45 7. Protocol Bindings ..............................................45
7.2.4. HTTP Status Codes . . . . . . . . . . . . . . . . . . 46 7.1. General Requirements ......................................45
7.2.5. HTTP Authentication . . . . . . . . . . . . . . . . . 46 7.2. HTTP/1.1 Binding for DSKPP ................................46
7.2.6. Initialization of DSKPP . . . . . . . . . . . . . . . 46 7.2.1. Identification of DSKPP Messages ...................46
7.2.7. Example Messages . . . . . . . . . . . . . . . . . . 47 7.2.2. HTTP Headers .......................................46
8. DSKPP XML Schema . . . . . . . . . . . . . . . . . . . . . . 47 7.2.3. HTTP Operations ....................................47
8.1. General Processing Requirements . . . . . . . . . . . . . 47 7.2.4. HTTP Status Codes ..................................47
8.2. Schema . . . . . . . . . . . . . . . . . . . . . . . . . 48 7.2.5. HTTP Authentication ................................47
9. Conformance Requirements . . . . . . . . . . . . . . . . . . 56 7.2.6. Initialization of DSKPP ............................47
10. Security Considerations . . . . . . . . . . . . . . . . . . . 58 7.2.7. Example Messages ...................................48
10.1. General . . . . . . . . . . . . . . . . . . . . . . . . . 58 8. DSKPP XML Schema ...............................................49
10.2. Active Attacks . . . . . . . . . . . . . . . . . . . . . 58 8.1. General Processing Requirements ...........................49
10.2.1. Introduction . . . . . . . . . . . . . . . . . . . . 58 8.2. Schema ....................................................49
10.2.2. Message Modifications . . . . . . . . . . . . . . . . 58 9. Conformance Requirements .......................................58
10.2.3. Message Deletion . . . . . . . . . . . . . . . . . . 60 10. Security Considerations .......................................59
10.2.4. Message Insertion . . . . . . . . . . . . . . . . . . 60 10.1. General ..................................................59
10.2.5. Message Replay . . . . . . . . . . . . . . . . . . . 60 10.2. Active Attacks ...........................................60
10.2.6. Message Reordering . . . . . . . . . . . . . . . . . 61 10.2.1. Introduction ......................................60
10.2.7. Man-in-the-Middle . . . . . . . . . . . . . . . . . . 61 10.2.2. Message Modifications .............................60
10.3. Passive Attacks . . . . . . . . . . . . . . . . . . . . . 61 10.2.3. Message Deletion ..................................61
10.4. Cryptographic Attacks . . . . . . . . . . . . . . . . . . 61 10.2.4. Message Insertion .................................62
10.5. Attacks on the Interaction between DSKPP and User 10.2.5. Message Replay ....................................62
Authentication . . . . . . . . . . . . . . . . . . . . . 62 10.2.6. Message Reordering ................................62
10.6. Miscellaneous Considerations . . . . . . . . . . . . . . 62 10.2.7. Man in the Middle .................................63
10.6.1. Client Contributions to K_TOKEN Entropy . . . . . . . 63 10.3. Passive Attacks ..........................................63
10.6.2. Key Confirmation . . . . . . . . . . . . . . . . . . 63 10.4. Cryptographic Attacks ....................................63
10.6.3. Server Authentication . . . . . . . . . . . . . . . . 63 10.5. Attacks on the Interaction between DSKPP and User
10.6.4. User Authentication . . . . . . . . . . . . . . . . . 63 Authentication ...........................................64
10.6.5. Key Protection in Two-Pass DSKPP . . . . . . . . . . 64 10.6. Miscellaneous Considerations .............................65
10.6.6. Algorithm Agility . . . . . . . . . . . . . . . . . . 65 10.6.1. Client Contributions to K_TOKEN Entropy ...........65
11. Internationalization Considerations . . . . . . . . . . . . . 65 10.6.2. Key Confirmation ..................................65
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 65 10.6.3. Server Authentication .............................65
12.1. URN Sub-Namespace Registration . . . . . . . . . . . . . 66 10.6.4. User Authentication ...............................66
12.2. XML Schema Registration . . . . . . . . . . . . . . . . . 66 10.6.5. Key Protection in Two-Pass DSKPP ..................66
12.3. MIME Media Type Registration . . . . . . . . . . . . . . 66 10.6.6. Algorithm Agility .................................67
12.4. Status Code Registration . . . . . . . . . . . . . . . . 67 11. Internationalization Considerations ...........................68
12.5. DSKPP Version Registration . . . . . . . . . . . . . . . 68 12. IANA Considerations ...........................................68
12.6. PRF Algorithm ID Sub-Registry . . . . . . . . . . . . . . 68 12.1. URN Sub-Namespace Registration ...........................68
12.6.1. DSKPP-PRF-AES . . . . . . . . . . . . . . . . . . . . 69 12.2. XML Schema Registration ..................................69
12.6.2. DSKPP-PRF-SHA256 . . . . . . . . . . . . . . . . . . 69 12.3. MIME Media Type Registration .............................69
12.7. Key Container Registration . . . . . . . . . . . . . . . 69 12.4. Status Code Registration .................................70
13. Intellectual Property Considerations . . . . . . . . . . . . 70 12.5. DSKPP Version Registration ...............................70
14. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 71 12.6. PRF Algorithm ID Sub-Registry ............................70
15. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 71 12.6.1. DSKPP-PRF-AES .....................................71
16. References . . . . . . . . . . . . . . . . . . . . . . . . . 72 12.6.2. DSKPP-PRF-SHA256 ..................................71
16.1. Normative references . . . . . . . . . . . . . . . . . . 72 12.7. Key Container Registration ...............................72
16.2. Informative references . . . . . . . . . . . . . . . . . 74 13. Intellectual Property Considerations ..........................73
Appendix A. Usage Scenarios . . . . . . . . . . . . . . . . . . 75 14. Contributors ..................................................73
A.1. Single Key Request . . . . . . . . . . . . . . . . . . . 75 15. Acknowledgements ..............................................73
A.2. Multiple Key Requests . . . . . . . . . . . . . . . . . . 76 16. References ....................................................74
A.3. User Authentication . . . . . . . . . . . . . . . . . . . 76 16.1. Normative References .....................................74
A.4. Provisioning Time-Out Policy . . . . . . . . . . . . . . 76 16.2. Informative References ...................................76
A.5. Key Renewal . . . . . . . . . . . . . . . . . . . . . . . 76 Appendix A. Usage Scenarios ......................................78
A.6. Pre-Loaded Key Replacement . . . . . . . . . . . . . . . 76 A.1. Single Key Request ........................................78
A.7. Pre-Shared Manufacturing Key . . . . . . . . . . . . . . 77 A.2. Multiple Key Requests .....................................78
A.8. End-to-End Protection of Key Material . . . . . . . . . . 77 A.3. User Authentication .......................................78
Appendix B. Examples . . . . . . . . . . . . . . . . . . . . . . 77 A.4. Provisioning Time-Out Policy ............................78
B.1. Trigger Message . . . . . . . . . . . . . . . . . . . . . 78 A.5. Key Renewal ...............................................79
B.2. Four-Pass Protocol . . . . . . . . . . . . . . . . . . . 78 A.6. Pre-Loaded Key Replacement ..............................79
B.2.1. <KeyProvClientHello> Without a Preceding Trigger . . 78 A.7. Pre-Shared Manufacturing Key ............................79
B.2.2. <KeyProvClientHello> Assuming a Preceding Trigger . . 79 A.8. End-to-End Protection of Key Material ...................80
B.2.3. <KeyProvServerHello> Without a Preceding Trigger . . 81 Appendix B. Examples .............................................80
B.2.4. <KeyProvServerHello> Assuming Key Renewal . . . . . . 82 B.1. Trigger Message ...........................................80
B.2.5. <KeyProvClientNonce> Using Default Encryption . . . . 82 B.2. Four-Pass Protocol ......................................81
B.2.6. <KeyProvServerFinished> Using Default Encryption . . 83 B.2.1. <KeyProvClientHello> without a Preceding Trigger ......81
B.3. Two-Pass Protocol . . . . . . . . . . . . . . . . . . . . 84 B.2.2. <KeyProvClientHello> Assuming a Preceding Trigger .....82
B.3.1. Example Using the Key Transport Method . . . . . . . 84 B.2.3. <KeyProvServerHello> Without a Preceding Trigger ......83
B.3.2. Example Using the Key Wrap Method . . . . . . . . . . 88 B.2.4. <KeyProvServerHello> Assuming Key Renewal .............84
B.3.3. Example Using the Passphrase-Based Key Wrap Method . 91 B.2.5. <KeyProvClientNonce> Using Default Encryption .........85
Appendix C. Integration with PKCS #11 . . . . . . . . . . . . . 95 B.2.6. <KeyProvServerFinished> Using Default Encryption ......85
C.1. The 4-pass Variant . . . . . . . . . . . . . . . . . . . 96 B.3. Two-Pass Protocol .......................................86
C.2. The 2-pass Variant . . . . . . . . . . . . . . . . . . . 96 B.3.1. Example Using the Key Transport Method ................86
Appendix D. Example of DSKPP-PRF Realizations . . . . . . . . . 98 B.3.2. Example Using the Key Wrap Method .....................90
D.1. Introduction . . . . . . . . . . . . . . . . . . . . . . 98 B.3.3. Example Using the Passphrase-Based Key Wrap Method ..94
D.2. DSKPP-PRF-AES . . . . . . . . . . . . . . . . . . . . . . 98 Appendix C. Integration with PKCS #11 ............................98
D.2.1. Identification . . . . . . . . . . . . . . . . . . . 98 C.1. The Four-Pass Variant ...................................98
D.2.2. Definition . . . . . . . . . . . . . . . . . . . . . 99 C.2. The Two-Pass Variant ....................................98
D.2.3. Example . . . . . . . . . . . . . . . . . . . . . . . 100 Appendix D. Example of DSKPP-PRF Realizations .................101
D.3. DSKPP-PRF-SHA256 . . . . . . . . . . . . . . . . . . . . 100 D.1. Introduction .............................................101
D.3.1. Identification . . . . . . . . . . . . . . . . . . . 100 D.2. DSKPP-PRF-AES ..........................................101
D.3.2. Definition . . . . . . . . . . . . . . . . . . . . . 100 D.2.1. Identification .......................................101
D.3.3. Example . . . . . . . . . . . . . . . . . . . . . . . 101 D.2.2. Definition ...........................................101
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 102 D.2.3. Example ..............................................102
D.3. DSKPP-PRF-SHA256 .......................................103
D.3.1. Identification .......................................103
D.3.2. Definition ...........................................103
D.3.3. Example ..............................................104
1. Introduction 1. Introduction
Symmetric key based cryptographic systems (e.g., those providing Symmetric-key-based cryptographic systems (e.g., those providing
authentication mechanisms such as one-time passwords and challenge- authentication mechanisms such as one-time passwords and challenge-
response) offer performance and operational advantages over public response) offer performance and operational advantages over public
key schemes. Such use requires a mechanism for provisioning of key schemes. Such use requires a mechanism for the provisioning of
symmetric keys providing equivalent functionality to mechanisms such symmetric keys providing equivalent functionality to mechanisms such
as CMP [RFC4210] and CMC [RFC5272] in a Public Key Infrastructure. as the Certificate Management Protocol (CMP) [RFC4210] and
Certificate Management over CMS (CMC) [RFC5272] in a Public Key
Infrastructure.
Traditionally, cryptographic modules have been provisioned with keys Traditionally, cryptographic modules have been provisioned with keys
during device manufacturing, and the keys have been imported to the during device manufacturing, and the keys have been imported to the
cryptographic server using, e.g., a CD-ROM disc shipped with the cryptographic server using, e.g., a CD-ROM disc shipped with the
devices. Some vendors also have proprietary provisioning protocols, devices. Some vendors also have proprietary provisioning protocols,
which often have not been publicly documented (CT-KIP is one which often have not been publicly documented (the Cryptographic
exception [RFC4758]). Token Key Initialization Protocol (CT-KIP) is one exception
[RFC4758]).
This document describes the Dynamic Symmetric Key Provisioning This document describes the Dynamic Symmetric Key Provisioning
Protocol (DSKPP), a client-server protocol for provisioning symmetric Protocol (DSKPP), a client-server protocol for provisioning symmetric
keys between a cryptographic module (corresponding to DSKPP client) keys between a cryptographic module (corresponding to DSKPP Client)
and a key provisioning server (corresponding to DSKPP server). and a key provisioning server (corresponding to DSKPP Server).
DSKPP provides an open and interoperable mechanism for initializing DSKPP provides an open and interoperable mechanism for initializing
and configuring symmetric keys to cryptographic modules that are and configuring symmetric keys to cryptographic modules that are
accessible over the Internet. The description is based on the accessible over the Internet. The description is based on the
information contained in [RFC4758], and contains specific information contained in [RFC4758], and contains specific
enhancements, such as User Authentication and support for the [PSKC] enhancements, such as user authentication and support for the
format for transmission of keying material. [RFC6030] format for transmission of keying material.
DSKPP has two principal protocol variants. The four-pass protocol DSKPP has two principal protocol variants. The four-pass protocol
variant permits a symmetric key to be established that includes variant permits a symmetric key to be established that includes
randomness contributed by both the client and the server. The two- randomness contributed by both the client and the server. The two-
pass protocol requires only one round trip instead of two and permits pass protocol requires only one round trip instead of two and permits
a server specified key to be established. a server specified key to be established.
1.1. Key Words 1.1. Key Words
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
skipping to change at page 7, line 4 skipping to change at page 7, line 8
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
1.2. Version Support 1.2. Version Support
There is a provision made in the syntax for an explicit version There is a provision made in the syntax for an explicit version
number. Only version "1.0" is currently specified. number. Only version "1.0" is currently specified.
The purpose for versioning the protocol is to provide a mechanism by The purpose for versioning the protocol is to provide a mechanism by
which changes to required cryptographic algorithms (e.g., SHA-256) which changes to required cryptographic algorithms (e.g., SHA-256)
and attributes (e.g., key size) can be deployed without disrupting and attributes (e.g., key size) can be deployed without disrupting
existing implementations; likewise, out-dated implementations can be existing implementations; likewise, outdated implementations can be
de-commissioned without disrupting operations involving newer de-commissioned without disrupting operations involving newer
protocol versions. protocol versions.
The numbering scheme for DSKPP versions is "<major>.<minor>". The The numbering scheme for DSKPP versions is "<major>.<minor>". The
major and minor numbers MUST be treated as separate integers and each major and minor numbers MUST be treated as separate integers and each
number MAY be incremented higher than a single digit. Thus, "DSKPP number MAY be incremented higher than a single digit. Thus, "DSKPP
2.4" would be a lower version than "DSKPP 2.13", which in turn would 2.4" would be a lower version than "DSKPP 2.13", which in turn would
be lower than "DSKPP 12.3". Leading zeros (e.g., "DSKPP 6.01") MUST be lower than "DSKPP 12.3". Leading zeros (e.g., "DSKPP 6.01") MUST
be ignored by recipients and MUST NOT be sent. be ignored by recipients and MUST NOT be sent.
The major version number should be incremented only if the data The major version number should be incremented only if the data
formats or security algorithms have changed so dramatically that an formats or security algorithms have changed so dramatically that an
older version implementation would not be able to interoperate with a older version implementation would not be able to interoperate with a
newer version (e.g., removing support for a previously mandatory-to- newer version (e.g., removing support for a previously mandatory-to-
implement algorithm now found to be insecure). The minor version implement algorithm now found to be insecure). The minor version
number indicates new capabilities (e.g., introducing a new algorithm number indicates new capabilities (e.g., introducing a new algorithm
option) and MUST be ignored by an entity with a smaller minor version option) and MUST be ignored by an entity with a smaller minor version
number, but used for informational purposes by the entity with the number but be used for informational purposes by the entity with the
larger minor version number. larger minor version number.
1.3. Namespace Identifiers 1.3. Namespace Identifiers
This document uses Uniform Resource Identifiers [RFC3986] to identify This document uses Uniform Resource Identifiers (URIs) [RFC3986] to
resources, algorithms, and semantics. identify resources, algorithms, and semantics.
1.3.1. Defined Identifiers 1.3.1. Defined Identifiers
The XML namespace [XMLNS] URI for Version 1.0 of DSKPP protocol is: The XML namespace [XMLNS] URI for Version 1.0 of DSKPP is:
"urn:ietf:params:xml:ns:keyprov:dskpp" "urn:ietf:params:xml:ns:keyprov:dskpp"
References to qualified elements in the DSKPP schema defined herein References to qualified elements in the DSKPP schema defined herein
use the prefix "dskpp", but any prefix is allowed. use the prefix "dskpp", but any prefix is allowed.
1.3.2. Identifiers Defined in Related Specifications 1.3.2. Identifiers Defined in Related Specifications
This document relies on qualified elements already defined in the This document relies on qualified elements already defined in the
Portable Symmetric Key Container [PSKC] namespace, which is Portable Symmetric Key Container [RFC6030] namespace, which is
represented by the prefix "pskc" and declared as: represented by the prefix "pskc" and declared as:
xmlns:pskc="urn:ietf:params:xml:ns:keyprov:pskc" xmlns:pskc="urn:ietf:params:xml:ns:keyprov:pskc"
1.3.3. Referenced Identifiers 1.3.3. Referenced Identifiers
Finally, the DSKPP syntax presented in this document relies on Finally, the DSKPP syntax presented in this document relies on
algorithm identifiers defined in the XML Signature [XMLDSIG] algorithm identifiers defined in the XML Signature [XMLDSIG]
namespace: namespace:
xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
References to algorithm identifiers in the XML Signature namespace References to algorithm identifiers in the XML Signature namespace
are represented by the prefix "ds". are represented by the prefix "ds".
2. Terminology 2. Terminology
2.1. Definitions 2.1. Definitions
The definitions provided below are defined as used in this document. Terms are defined below as they are used in this document. The same
The same terms may be defined differently in other documents. terms may be defined differently in other documents.
Authentication Code (AC): User Authentication Code comprised of a Authentication Code (AC): User Authentication Code comprised of a
string of hexadecimal characters known to the device and the string of hexadecimal characters known to the device and the
server and containing at a minimum a client identifier and a server and containing at a minimum a client identifier and a
password. This ClientID/password combination is used only once password. This ClientID/password combination is used only once
and may have a time limit, and then discarded. and may have a time limit, and then discarded.
Authentication Data (AD): User Authentication Data that is derived Authentication Data (AD): User Authentication Data that is derived
from the Authentication Code (AC) from the Authentication Code (AC)
Client ID: An identifier that the DSKPP Server uses to locate the Client ID: An identifier that the DSKPP Server uses to locate the
real user name or account identifier on the server. It can be a real username or account identifier on the server. It can be a
short random identifier that is unrelated to any real usernames. short random identifier that is unrelated to any real usernames.
Cryptographic Module: A component of an application, which enables Cryptographic Module: A component of an application, which enables
symmetric key cryptographic functionality symmetric key cryptographic functionality
Device: A physical piece of hardware, or a software framework, that Device: A physical piece of hardware, or a software framework, that
hosts symmetric key cryptographic modules hosts symmetric key cryptographic modules
Device ID (DeviceID): A unique identifier for the device that houses Device ID (DeviceID): A unique identifier for the device that houses
the cryptographic module, e.g., a mobile phone the cryptographic module, e.g., a mobile phone
DSKPP Client: Manages communication between the symmetric key DSKPP Client: Manages communication between the symmetric key
cryptographic module and the DSKPP server cryptographic module and the DSKPP Server
DSKPP Server: The symmetric key provisioning server that DSKPP Server: The symmetric key provisioning server that
participates in the DSKPP protocol run participates in the DSKPP run
DSKPP Server ID (ServerID): The unique identifier of a DSKPP server DSKPP Server ID (ServerID): The unique identifier of a DSKPP Server
Key Agreement: A key establishment protocol whereby two or more Key Agreement: A key establishment protocol whereby two or more
parties can agree on a key in such a way that both influence the parties can agree on a key in such a way that both influence the
outcome outcome
Key Confirmation: The assurance of the rightful participants in a Key Confirmation: The assurance of the rightful participants in a
key-establishment protocol that the intended recipient of the key-establishment protocol that the intended recipient of the
shared key actually possesses the shared key shared key actually possesses the shared key
Key Issuer: An organization that issues symmetric keys to end-users Key Issuer: An organization that issues symmetric keys to end-users
Key Package (KP): An object that encapsulates a symmetric key and Key Package (KP): An object that encapsulates a symmetric key and
its configuration data its configuration data
Key ID (KeyID): A unique identifier for the symmetric key Key ID (KeyID): A unique identifier for the symmetric key
Key Protection Method (KPM): The key transport method used during Key Protection Method (KPM): The key transport method used during
two-pass DSKPP two-pass DSKPP
Key Protection Method List (KPML): The list of key protection Key Protection Method List (KPML): The list of key protection
methods supported by a cryptographic module methods supported by a cryptographic module
Key Provisioning Server: A lifecycle management system that provides Key Provisioning Server: A lifecycle management system that provides
a key issuer with the ability to provision keys to cryptographic a key issuer with the ability to provision keys to cryptographic
modules hosted on end-users' devices modules hosted on end-users' devices
Key Transport: A key establishment procedure whereby the DSKPP Key Transport: A key establishment procedure whereby the DSKPP
server selects and encrypts the keying material and then sends Server selects and encrypts the keying material and then sends the
the material to the DSKPP client [NIST-SP800-57] material to the DSKPP Client [NIST-SP800-57]
Key Transport Key: The private key that resides on the cryptographic Key Transport Key: The private key that resides on the cryptographic
module. This key is paired with the DSKPP client's public key, module. This key is paired with the DSKPP Client's public key,
which the DSKPP server uses to encrypt keying material during key which the DSKPP Server uses to encrypt keying material during key
transport [NIST-SP800-57] transport [NIST-SP800-57]
Key Type: The type of symmetric key cryptographic methods for which Key Type: The type of symmetric key cryptographic methods for which
the key will be used (e.g., OATH HOTP or RSA SecurID the key will be used (e.g., Open AUTHentication HMAC-Based One-
authentication, AES encryption, etc.) Time Password (OATH HOTP) or RSA SecurID authentication, AES
encryption, etc.)
Key Wrapping: A method of encrypting keys for key transport Key Wrapping: A method of encrypting keys for key transport
[NIST-SP800-57] [NIST-SP800-57]
Key Wrapping Key: A symmetric key encrypting key used for key Key Wrapping Key: A symmetric key encrypting key used for key
wrapping [NIST-SP800-57] wrapping [NIST-SP800-57]
Keying Material: The data necessary (e.g., keys and key Keying Material: The data necessary (e.g., keys and key
configuration data) necessary to establish and maintain configuration data) necessary to establish and maintain
cryptographic keying relationships [NIST-SP800-57] cryptographic keying relationships [NIST-SP800-57]
Manufacturer's Key A unique master key pre-issued to a hardware Manufacturer's Key: A unique master key pre-issued to a hardware
device, e.g., a smart card, during the manufacturing process. If device, e.g., a smart card, during the manufacturing process. If
present, this key may be used by a cryptographic module to derive present, this key may be used by a cryptographic module to derive
secret keys secret keys
Protocol Run: Complete execution of the DSKPP that involves one Protocol Run: Complete execution of the DSKPP that involves one
exchange (2-pass) or two exchanges (4-pass) exchange (two-pass) or two exchanges (four-pass)
Security Attribute List (SAL): A payload that contains the DSKPP Security Attribute List (SAL): A payload that contains the DSKPP
version, DSKPP variant (four- or two-pass), key package formats, version, DSKPP variant (four- or two-pass), key package formats,
key types, and cryptographic algorithms that the cryptographic key types, and cryptographic algorithms that the cryptographic
module is capable of supporting module is capable of supporting
2.2. Notation 2.2. Notation
|| String concatenation || String concatenation
[x] Optional element x [x] Optional element x
A ^ B Exclusive-OR operation on strings A and B (where A ^ B Exclusive-OR operation on strings A and B
A and B are of equal length) (where A and B are of equal length)
<XMLElement> A typographical convention used in the body of <XMLElement> A typographical convention used in the body of
the text the text
DSKPP-PRF(k,s,dsLen) A keyed pseudo-random function DSKPP-PRF(k,s,dsLen) A keyed pseudorandom function
E(k,m) Encryption of m with the key k E(k,m) Encryption of m with the key k
K Key used to encrypt R_C (either K_SERVER or K Key used to encrypt R_C (either K_SERVER or
K_SHARED), or in MAC or DSKPP_PRF computations K_SHARED), or in MAC or DSKPP_PRF computations
K_AC Secret key that is derived from the K_AC Secret key that is derived from the
Authentication Code and used for user Authentication Code and used for user
authentication purposes authentication purposes
K_MAC Secret key derived during a DSKPP exchange for K_MAC Secret key derived during a DSKPP exchange for
use with key confirmation use with key confirmation
K_MAC' A second secret key used for server K_MAC' A second secret key used for server
authentication authentication
K_PROV A provisioning master key from which two keys are K_PROV A provisioning master key from which two keys
derived: K_TOKEN and K_MAC are derived: K_TOKEN and K_MAC
K_SERVER Public key of the DSKPP server; used for K_SERVER Public key of the DSKPP Server; used for
encrypting R_C in the four-pass protocol variant encrypting R_C in the four-pass protocol
K_SHARED Secret key that is pre-shared between the DSKPP variant
client and the DSKPP server; used for encrypting
R_C in the four-pass protocol variant
K_TOKEN Secret key that is established in a cryptographic
module using DSKPP
R Pseudorandom value chosen by the DSKPP client and
used for MAC computations
R_C Pseudorandom value chosen by the DSKPP client and K_SHARED Secret key that is pre-shared between the DSKPP
used as input to the generation of K_TOKEN Client and the DSKPP Server; used for
R_S Pseudorandom value chosen by the DSKPP server and encrypting R_C in the four-pass protocol
used as input to the generation of K_TOKEN variant
URL_S DSKPP server address, as a URL K_TOKEN Secret key that is established in a
cryptographic module using DSKPP
R Pseudorandom value chosen by the DSKPP Client
and used for MAC computations
R_C Pseudorandom value chosen by the DSKPP Client
and used as input to the generation of K_TOKEN
R_S Pseudorandom value chosen by the DSKPP Server
and used as input to the generation of K_TOKEN
URL_S DSKPP Server address, as a URL
2.3. Abbreviations 2.3. Abbreviations
AC Authentication Code AC Authentication Code
AD Authentication Data AD Authentication Data
DSKPP Dynamic Symmetric Key Provisioning Protocol DSKPP Dynamic Symmetric Key Provisioning Protocol
HTTP Hypertext Transfer Protocol HTTP Hypertext Transfer Protocol
KP Key Package KP Key Package
KPM Key Protection Method KPM Key Protection Method
KPML Key Protection Method List KPML Key Protection Method List
MAC Message Authentication Code MAC Message Authentication Code
PC Personal Computer PC Personal Computer
PDU Protocol Data Unit PDU Protocol Data Unit
PKCS Public-Key Cryptography Standards PKCS Public Key Cryptography Standards
PRF Pseudo-Random Function PRF Pseudorandom Function
PSKC Portable Symmetric Key Container PSKC Portable Symmetric Key Container
SAL Security Attribute List (see Section 2.1) SAL Security Attribute List (see Section 2.1)
TLS Transport Layer Security TLS Transport Layer Security
URL Uniform Resource Locator URL Uniform Resource Locator
USB Universal Serial Bus USB Universal Serial Bus
XML eXtensible Markup Language XML eXtensible Markup Language
3. DSKPP Overview 3. DSKPP Overview
The following sub-sections provide a high-level view of protocol The following sub-sections provide a high-level view of protocol
internals and how they interact with external provisioning internals and how they interact with external provisioning
applications. Usage scenarios are provided in Appendix A. applications. Usage scenarios are provided in Appendix A.
3.1. Protocol Entities 3.1. Protocol Entities
A DSKPP provisioning transaction has three entities: A DSKPP provisioning transaction has three entities:
Server: The DSKPP provisioning server. Server: The DSKPP provisioning server.
Cryptographic Module: The cryptographic module to which the Cryptographic Module: The cryptographic module to which the
symmetric keys are to be provisioned, e.g., an authentication symmetric keys are to be provisioned, e.g., an authentication
token. token.
Client: The DSKPP client which manages communication between the Client: The DSKPP Client that manages communication between the
cryptographic module and the key provisioning server. cryptographic module and the key provisioning server.
The principal syntax is XML [XML] and it is layered on a transport The principal syntax is XML [XML] and it is layered on a transport
mechanism such as HTTP [RFC2616] and HTTP Over TLS [RFC2818]. While mechanism such as HTTP [RFC2616] and HTTP Over TLS [RFC2818]. While
it is highly desirable for the entire communication between the DSKPP it is highly desirable for the entire communication between the DSKPP
client and server to be protected by means of a transport providing Client and server to be protected by means of a transport providing
confidentiality and integrity protection such as HTTP over Transport confidentiality and integrity protection such as HTTP over Transport
Layer Security (TLS), such protection is not sufficient to protect Layer Security (TLS), such protection is not sufficient to protect
the exchange of the symmetric key data between the server and the the exchange of the symmetric key data between the server and the
cryptographic module and the DSKPP protocol is designed to permit cryptographic module and DSKPP is designed to permit implementations
implementations that satisfy this requirement. that satisfy this requirement.
The server only communicates to the client. As far as the server is The server only communicates to the client. As far as the server is
concerned, the client and cryptographic module may be considered to concerned, the client and cryptographic module may be considered to
be a single entity. be a single entity.
From a client-side security perspective, however, the client and the From a client-side security perspective, however, the client and the
cryptographic module are separate logical entities and may in some cryptographic module are separate logical entities and may in some
implementations be separate physical entities as well. implementations be separate physical entities as well.
It is assumed that a device will host an application layered above It is assumed that a device will host an application layered above
the cryptographic module, and this application will manage the cryptographic module, and this application will manage
communication between the DSKPP client and cryptographic module. The communication between the DSKPP Client and cryptographic module. The
manner in which the communicating application will transfer DSKPP manner in which the communicating application will transfer DSKPP
protocol elements to and from the cryptographic module is transparent elements to and from the cryptographic module is transparent to the
to the DSKPP server. One method for this transfer is described in DSKPP Server. One method for this transfer is described in
[CT-KIP-P11]. [CT-KIP-P11].
3.2. Basic DSKPP Exchange 3.2. Basic DSKPP Exchange
3.2.1. User Authentication 3.2.1. User Authentication
In a DSKPP message flow, the user has obtained a new hardware or In a DSKPP message flow, the user has obtained a new hardware or
software device embedded with a cryptographic module. The goal of software device embedded with a cryptographic module. The goal of
DSKPP is to provision the same symmetric key and related information DSKPP is to provision the same symmetric key and related information
to the cryptographic module and the key management server, and to the cryptographic module and the key management server, and
associate the key with the correct user name (or other account associate the key with the correct username (or other account
identifier) on the server. To do this, the DSKPP Server MUST identifier) on the server. To do this, the DSKPP Server MUST
authenticate the user to be sure he is authorized for the new key. authenticate the user to be sure he is authorized for the new key.
User authentication occurs within the protocol itself after__ the User authentication occurs within the protocol itself *after* the
DSKPP client initiates the first message. In this case, the DSKPP DSKPP Client initiates the first message. In this case, the DSKPP
client MUST have access to the DSKPP Server URL. Client MUST have access to the DSKPP Server URL.
Alternatively, a DSKPP web service or other form of web application Alternatively, a DSKPP web service or other form of web application
can authenticate a user before__ the first message is exchanged. In can authenticate a user *before* the first message is exchanged. In
this case, the DSKPP server MUST trigger the DSKPP client to initiate this case, the DSKPP Server MUST trigger the DSKPP Client to initiate
the first message in the protocol transaction. the first message in the protocol transaction.
3.2.2. Protocol Initiated by the DSKPP Client 3.2.2. Protocol Initiated by the DSKPP Client
In the following example, the DSKPP client first initiates DSKPP, and In the following example, the DSKPP Client first initiates DSKPP, and
then the user is authenticated using a Client ID and Authentication then the user is authenticated using a Client ID and Authentication
Code. Code.
Crypto DSKPP DSKPP Key Provisioning Crypto DSKPP DSKPP Key Provisioning
Module Client Server Server Module Client Server Server
| | | | | | | |
| | | +---------------+ | | | +---------------+
| | | |Server creates | | | | |Server creates |
| | | |and stores | | | | |and stores |
| | | |Client ID and | | | | |Client ID and |
| | | |Auth. Code and | | | | |Auth. Code and |
| | | |delivers them | | | | |delivers them |
| | | |to user out-of-| | | | |to user out-of-|
skipping to change at page 14, line 4 skipping to change at page 15, line 9
| | | | | | | |
|<-- Key | | Key -->| |<-- Key | | Key -->|
| Package | | Package | | Package | | Package |
Figure 1: Basic DSKPP Exchange Figure 1: Basic DSKPP Exchange
Before DSKPP begins: Before DSKPP begins:
o The Authentication Code is generated by the DSKPP Server, and o The Authentication Code is generated by the DSKPP Server, and
delivered to the user via an out-of-band trustworthy channel delivered to the user via an out-of-band trustworthy channel
(e.g., a paper slip delivered by IT department staff). (e.g., a paper slip delivered by IT department staff).
o The user typically enters the Client ID and Authentication Code o The user typically enters the Client ID and Authentication Code
manually, possibly on a device with only numeric keypad. Thus, manually, possibly on a device with only a numeric keypad. Thus,
they are often short numeric values (for example, 8 decimal they are often short numeric values (for example, 8 decimal
digits). However, the DSKPP Server is free to generate them in digits). However, the DSKPP Server is free to generate them in
any way it wishes. any way it wishes.
o The DSKPP client needs the URL [RFC3986] of the DSKPP server o The DSKPP Client needs the URL [RFC3986] of the DSKPP Server
(which is not user-specific or secret, and may be pre-configured (which is not user specific or secret, and may be pre-configured
somehow), and a set of trust anchors for verifying the server somehow), and a set of trust anchors for verifying the server
certificate. certificate.
o There must be an account for the user that has an identifier and o There must be an account for the user that has an identifier and
long-term user name (or other account identifier) to which the long-term username (or other account identifier) to which the
token will be associated. The DSKPP server will use the Client ID token will be associated. The DSKPP Server will use the Client ID
to find the corresponding Authentication Code for user to find the corresponding Authentication Code for user
authentication. authentication.
In Step 1, the client establishes a TLS connection, and authenticates In Step 1, the client establishes a TLS connection, authenticates the
the server (that is, validates the certificate, and compares the host server (that is, validates the certificate, and compares the host
name in the URL with the certificate) as described in Section 3.1 of name in the URL with the certificate) as described in Section 3.1 of
[RFC2818]. [RFC2818].
Next, the DSKPP Client and DSKPP Server exchange DSKPP messages Next, the DSKPP Client and DSKPP Server exchange DSKPP messages
(which are sent over HTTPS). In these messages: (which are sent over HTTPS). In these messages:
o The client and server negotiate which cryptographic algorithms o The client and server negotiate which cryptographic algorithms
they want to use; which algorithms are supported for protecting they want to use, which algorithms are supported for protecting
DSKPP messages, and other DSKPP protocol details. DSKPP messages, and other DSKPP details.
o The client sends the Client ID to the server, and proves that it o The client sends the Client ID to the server, and proves that it
knows the corresponding Authentication Code. knows the corresponding Authentication Code.
o The client and server agree on a secret key (token key or o The client and server agree on a secret key (token key or
K_TOKEN); depending on the negotiated protocol variant, this is K_TOKEN); depending on the negotiated protocol variant, this is
either a fresh key derived during the DSKPP protocol run (called either a fresh key derived during the DSKPP run (called "four-pass
"four-pass variant", since it involves four DSKPP messages), or it variant", since it involves four DSKPP messages) or is generated
is generated by (or pre-exists on) the server and transported to by (or pre-exists on) the server and transported to the client
the client (called "two-pass variant" in the rest of this (called "two-pass variant" in the rest of this document, since it
document, since it involves two DSKPP messages). involves two DSKPP messages).
o The server sends a "key package" to the client. The package only o The server sends a "key package" to the client. The package only
includes the key itself in the case of the "two-pass variant"; includes the key itself in the case of the "two-pass variant";
with either variant, the key package contains attributes that with either variant, the key package contains attributes that
influence how the provisioned key will be later used by the influence how the provisioned key will be later used by the
cryptographic module and cryptographic server. The exact contents cryptographic module and cryptographic server. The exact contents
depend on the cryptographic algorithm (e.g., for a one-time depend on the cryptographic algorithm (e.g., for a one-time
password algorithm that supports variable-length OTP values, the password algorithm that supports variable-length OTP values, the
length of the OTP value would be one attribute in the key length of the OTP value would be one attribute in the key
package). package).
After the protocol run has been successfully completed, the After the protocol run has been successfully completed, the
cryptographic modules stores the contents of the key package. cryptographic modules stores the contents of the key package.
Likewise, the DSKPP provisioning server stores the contents of the Likewise, the DSKPP provisioning server stores the contents of the
key package with the cryptographic server, and associates these with key package with the cryptographic server, and associates these with
the correct user name. The user can now use the their device to the correct username. The user can now use the their device to
perform symmetric-key based operations. perform symmetric-key based operations.
The exact division of work between the cryptographic module and the The exact division of work between the cryptographic module and the
DSKPP client -- and key Provisioning server and DSKPP server -- are DSKPP Client -- and key Provisioning server and DSKPP Server -- are
not specified in this document. The figure above shows one possible not specified in this document. The figure above shows one possible
case, but this is intended for illustrative purposes only. case, but this is intended for illustrative purposes only.
3.2.3. Protocol Triggered by the DSKPP Server 3.2.3. Protocol Triggered by the DSKPP Server
In the first message flow (previous section), the Client ID and In the first message flow (previous section), the Client ID and
Authentication Code were delivered to the client by some out-of-band Authentication Code were delivered to the client by some out-of-band
means (such as paper sent to the user). means (such as paper sent to the user).
Web DSKPP DSKPP Web Web DSKPP DSKPP Web
skipping to change at page 15, line 39 skipping to change at page 16, line 44
| Trigger ---->| | | | Trigger ---->| | |
| | | | | | | |
| |<-- 1. TLS handshake with --->| | | |<-- 1. TLS handshake with --->| |
| | server auth. | | | | server auth. | |
| | | | | | | |
| | ... continues... | | | | ... continues... | |
Figure 2: DSKPP Exchange with Web-Based Authentication Figure 2: DSKPP Exchange with Web-Based Authentication
In the second message flow, the user first authenticates to a web In the second message flow, the user first authenticates to a web
server (for example, IT department's "self-service" Intranet page), server (for example, an IT department's "self-service" Intranet
using an ordinary web browser and some existing credentials. page), using an ordinary web browser and some existing credentials.
The user then requests (by clicking a link or submitting a form) The user then requests (by clicking a link or submitting a form)
provisioning of a new key to the cryptographic module. The web provisioning of a new key to the cryptographic module. The web
server will reply with a <KeyProvTrigger> message that contains the server will reply with a <KeyProvTrigger> message that contains the
Client ID, Authentication Code, and URL of the DSKPP server. This Client ID, Authentication Code, and URL of the DSKPP Server. This
information is also needed by the DSKPP server; how the web server information is also needed by the DSKPP Server; how the web server
and DSKPP server interact is beyond the scope of this document. and DSKPP Server interact is beyond the scope of this document.
The <KeyProvTrigger> message is sent in a HTTP response, and it is The <KeyProvTrigger> message is sent in an HTTP response, and it is
marked with MIME type "application/dskpp+xml". It is assumed the web marked with MIME type "application/dskpp+xml". It is assumed the web
browser has been configured to recognize this MIME type; the browser browser has been configured to recognize this MIME type; the browser
will start the DSKPP client, and provides it with the will start the DSKPP Client and provide it with the <KeyProvTrigger>
<KeyProvTrigger> message. message.
The DSKPP client then contacts the DSKPP server, and uses the Client The DSKPP Client then contacts the DSKPP Server and uses the Client
ID and Authentication Code (from the <KeyProvTrigger> message) the ID and Authentication Code (from the <KeyProvTrigger> message) the
same way as in the first message flow. same way as in the first message flow.
3.2.4. Variants 3.2.4. Variants
As noted in the previous section, once the protocol has started, the As noted in the previous section, once the protocol has started, the
client and server MAY engage in either a two-pass or four-pass client and server MAY engage in either a two-pass or four-pass
message exchange. The four-pass and two-pass protocols are message exchange. The four-pass and two-pass protocols are
appropriate in different deployment scenarios. The biggest appropriate in different deployment scenarios. The biggest
differentiator between the two is that the two-pass protocol supports differentiator between the two is that the two-pass protocol supports
transport of an existing key to a cryptographic module, while the transport of an existing key to a cryptographic module, while the
four-pass involves key generation on-the-fly via key agreement. In four-pass involves key generation on-the-fly via key agreement. In
either case, both protocol variants support algorithm agility through either case, both protocol variants support algorithm agility through
negotiation of encryption mechanisms and key types at the beginning the negotiation of encryption mechanisms and key types at the
of each protocol run. beginning of each protocol run.
3.2.4.1. Criteria for Using the Four-Pass Variant 3.2.4.1. Criteria for Using the Four-Pass Variant
The four-pass protocol is needed under one or more of the following The four-pass protocol is needed under one or more of the following
conditions: conditions:
o Policy requires that both parties engaged in the protocol jointly o Policy requires that both parties engaged in the protocol jointly
contribute entropy to the key. Enforcing this policy mitigates contribute entropy to the key. Enforcing this policy mitigates
the risk of exposing a key during the provisioning process as the the risk of exposing a key during the provisioning process as the
key is generated through mutual agreement without being key is generated through mutual agreement without being
transferred over-the-air or over-the-wire. It also mitigates risk transferred over-the-air or over-the-wire. It also mitigates risk
of exposure after the key is provisioned, as the key will not be of exposure after the key is provisioned, as the key will not be
vulnerable to a single point of attack in the system. vulnerable to a single point of attack in the system.
o A cryptographic module does not have private-key capabilities.
o The cryptographic module is hosted by a device that was neither o A cryptographic module does not have private key capabilities.
o The cryptographic module is hosted by a device that neither was
pre-issued with a manufacturer's key or other form of pre-shared pre-issued with a manufacturer's key or other form of pre-shared
key (as might be the case with a smart card or SIM card) nor has a key (as might be the case with a smart card or Subscriber Identity
keypad that can be used for entering a passphrase (such as present Module (SIM) card) nor has a keypad that can be used for entering
on a mobile phone). a passphrase (such as present on a mobile phone).
3.2.4.2. Criteria for Using the Two-Pass Variant 3.2.4.2. Criteria for Using the Two-Pass Variant
The two-pass protocol is needed under one or more of the following The two-pass protocol is needed under one or more of the following
conditions: conditions:
o Pre-existing (i.e., legacy) keys must be provisioned via transport o Pre-existing (i.e., legacy) keys must be provisioned via transport
to the cryptographic module. to the cryptographic module.
o The cryptographic module is hosted on a device that was pre-issued o The cryptographic module is hosted on a device that was pre-issued
with a manufacturer's key (such as may exist on a smart card), or with a manufacturer's key (such as may exist on a smart card), or
other form of pre-shared key (such as may exist on a SIM-card), other form of pre-shared key (such as may exist on a SIM-card),
and is capable of performing private-key operations. and is capable of performing private key operations.
o The cryptographic module is hosted by a device that has a built-in o The cryptographic module is hosted by a device that has a built-in
keypad with which a user may enter a passphrase, useful for keypad with which a user may enter a passphrase, useful for
deriving a key wrapping key for distribution of keying material. deriving a key wrapping key for distribution of keying material.
3.3. Status Codes 3.3. Status Codes
Upon transmission or receipt of a message for which the Status Upon transmission or receipt of a message for which the Status
attribute's value is not "Success" or "Continue", the default attribute's value is not "Success" or "Continue", the default
behavior, unless explicitly stated otherwise below, is that both the behavior, unless explicitly stated otherwise below, is that both the
DSKPP server and the DSKPP client MUST immediately terminate the DSKPP Server and the DSKPP Client MUST immediately terminate the
DSKPP protocol run. DSKPP servers and DSKPP clients MUST delete any DSKPP run. DSKPP Servers and DSKPP Clients MUST delete any secret
secret values generated as a result of failed runs of the DSKPP values generated as a result of failed runs of DSKPP. Session
protocol. Session identifiers MAY be retained from successful or identifiers MAY be retained from successful or failed protocol runs
failed protocol runs for replay detection purposes, but such retained for replay detection purposes, but such retained identifiers MUST NOT
identifiers MUST NOT be reused for subsequent runs of the protocol. be reused for subsequent runs of the protocol.
When possible, the DSKPP client SHOULD present an appropriate error When possible, the DSKPP Client SHOULD present an appropriate error
message to the user. message to the user.
These status codes are valid in all DSKPP Response messages unless These status codes are valid in all DSKPP Response messages unless
explicitly stated otherwise: explicitly stated otherwise:
Continue: The DSKPP server is ready for a subsequent request from Continue: The DSKPP Server is ready for a subsequent request from
the DSKPP client. It cannot be sent in the server's final the DSKPP Client. It cannot be sent in the server's final
message message.
Success: Successful completion of the DSKPP session. It can only be Success: Successful completion of the DSKPP session. It can only be
sent in the server's final message sent in the server's final message.
Abort: The DSKPP server rejected the DSKPP client's request for Abort: The DSKPP Server rejected the DSKPP Client's request for
unspecified reasons unspecified reasons.
AccessDenied: The DSKPP client is not authorized to contact this AccessDenied: The DSKPP Client is not authorized to contact this
DSKPP server DSKPP Server.
MalformedRequest: The DSKPP server failed to parse the DSKPP MalformedRequest: The DSKPP Server failed to parse the DSKPP
client's request Client's request.
UnknownRequest: The DSKPP client made a request that is unknown to UnknownRequest: The DSKPP Client made a request that is unknown to
the DSKPP server the DSKPP Server.
UnknownCriticalExtension: A DSKPP extension marked as "Critical" UnknownCriticalExtension: A DSKPP extension marked as "Critical"
could not be interpreted by the receiving party. could not be interpreted by the receiving party.
UnsupportedVersion: The DSKPP client used a DSKPP protocol version UnsupportedVersion: The DSKPP Client used a DSKPP version not
not supported by the DSKPP server. This error is only valid in supported by the DSKPP Server. This error is only valid in the
the DSKPP server's first response message DSKPP Server's first response message.
NoSupportedKeyTypes: "NoSupportedKeyTypes" indicates that the DSKPP NoSupportedKeyTypes: "NoSupportedKeyTypes" indicates that the DSKPP
client only suggested key types that are not supported by the Client only suggested key types that are not supported by the
DSKPP server. This error is only valid in the DSKPP server's DSKPP Server. This error is only valid in the DSKPP Server's
first response message first response message.
NoSupportedEncryptionAlgorithms: The DSKPP client only suggested NoSupportedEncryptionAlgorithms: The DSKPP Client only suggested
encryption algorithms that are not supported by the DSKPP server. encryption algorithms that are not supported by the DSKPP Server.
This error is only valid in the DSKPP server's first response This error is only valid in the DSKPP Server's first response
message message.
NoSupportedMacAlgorithms: The DSKPP client only suggested MAC NoSupportedMacAlgorithms: The DSKPP Client only suggested MAC
algorithms that are not supported by the DSKPP server. This algorithms that are not supported by the DSKPP Server. This error
error is only valid in the DSKPP server's first response message is only valid in the DSKPP Server's first response message.
NoProtocolVariants: The DSKPP client did not suggest a required NoProtocolVariants: The DSKPP Client did not suggest a required
protocol variant (either 2-pass or 4-pass). This error is only protocol variant (either two-pass or four-pass). This error is
valid in the DSKPP server's first response message. only valid in the DSKPP Server's first response message.
NoSupportedKeyPackages: The DSKPP client only suggested key package NoSupportedKeyPackages: The DSKPP Client only suggested key package
formats that are not supported by the DSKPP server. This error formats that are not supported by the DSKPP Server. This error is
is only valid in the DSKPP server's first response message only valid in the DSKPP Server's first response message.
AuthenticationDataMissing: The DSKPP client didn't provide AuthenticationDataMissing: The DSKPP Client didn't provide
authentication data that the DSKPP server required Authentication Data that the DSKPP Server required.
AuthenticationDataInvalid: The DSKPP client supplied user AuthenticationDataInvalid: The DSKPP Client supplied User
authentication data that the DSKPP server failed to validate Authentication Data that the DSKPP Server failed to validate.
InitializationFailed: The DSKPP server could not generate a valid InitializationFailed: The DSKPP Server could not generate a valid
key given the provided data. When this status code is received, key given the provided data. When this status code is received,
the DSKPP client SHOULD try to restart DSKPP, as it is possible the DSKPP Client SHOULD try to restart DSKPP, as it is possible
that a new run will succeed that a new run will succeed.
ProvisioningPeriodExpired: The provisioning period set by the DSKPP ProvisioningPeriodExpired: The provisioning period set by the DSKPP
server has expired. When the status code is received, the DSKPP Server has expired. When the status code is received, the DSKPP
client SHOULD report the reason for key initialization failure to Client SHOULD report the reason for key initialization failure to
the user and the user MUST register with the DSKPP server to the user and the user MUST register with the DSKPP Server to
initialize a new key initialize a new key.
3.4. Basic Constructs 3.4. Basic Constructs
The following calculations are used in both DSKPP protocol variants. The following calculations are used in both DSKPP variants.
3.4.1. User Authentication Data, AD 3.4.1. User Authentication Data (AD)
User authentication data (AD) is derived from a Client ID and User Authentication Data (AD) is derived from a Client ID and
Authentication Code that the user enters before the first DSKPP Authentication Code that the user enters before the first DSKPP
message is sent. message is sent.
Note: The user will typically enter the Client ID and Authentication Note: The user will typically enter the Client ID and Authentication
Code manually, possibly on a device with only numeric keypad. Thus, Code manually, possibly on a device with only numeric keypad. Thus,
they are often short numeric values (for example, 8 decimal digits). they are often short numeric values (for example, 8 decimal digits).
However, the DSKPP Server is free to generate them in any way it However, the DSKPP Server is free to generate them in any way it
wishes. wishes.
3.4.1.1. Authentication Code Format 3.4.1.1. Authentication Code Format
skipping to change at page 20, line 22 skipping to change at page 21, line 28
| 3 | Checksum | Optional | { "4D5" } | | 3 | Checksum | Optional | { "4D5" } |
+------+------------+-------------+-----------------------------+ +------+------------+-------------+-----------------------------+
The Client ID is a mandatory TLV that represents the requester's The Client ID is a mandatory TLV that represents the requester's
identifier of maximum length 255. The value is represented as a identifier of maximum length 255. The value is represented as a
string of hexadecimal characters that identifies the key request. string of hexadecimal characters that identifies the key request.
For example, suppose Client ID is set to "AC00000A", the Client ID For example, suppose Client ID is set to "AC00000A", the Client ID
TLV in the AC will be represented as "108AC00000A". TLV in the AC will be represented as "108AC00000A".
The Password is a mandatory TLV the contains a one-time use shared The Password is a mandatory TLV the contains a one-time use shared
secret known by the user and the Provisioning Server. The password secret known by the user and the Provisioning Server. The Password
value is unique and SHOULD be a random string to make AC more value is unique and SHOULD be a random string to make AC more
difficult to guess. The string MUST contain hexadecimal characters difficult to guess. The string MUST contain hexadecimal characters
only. For example, suppose password is set to "3582AF0C3E", then the only. For example, suppose password is set to "3582AF0C3E", then the
Password TLV would be "20A3582AF0C3E". Password TLV would be "20A3582AF0C3E".
The Checksum is an OPTIONAL TLV, which is generated by the issuing The Checksum is an OPTIONAL TLV, which is generated by the issuing
server and sent to the user as part of the AC. If the TLV is server and sent to the user as part of the AC. If the TLV is
provided, the checksum value MUST be computed using the CRC16 provided, the checksum value MUST be computed using the CRC16
algorithm [ISO3309]. When the user enters the AC, the typed AC algorithm [ISO3309]. When the user enters the AC, the typed AC
string of characters is verified with the checksum to ensure it is string of characters is verified with the checksum to ensure it is
skipping to change at page 20, line 51 skipping to change at page 22, line 8
only for the AC at the application's user interface layer and making only for the AC at the application's user interface layer and making
the TLV triples non-transparent to the user as described in the the TLV triples non-transparent to the user as described in the
example above; implementations MAY additionally choose to use other example above; implementations MAY additionally choose to use other
printable Unicode characters [UNICODE] at the application's user printable Unicode characters [UNICODE] at the application's user
interface layer in order to meet specific local, context or usability interface layer in order to meet specific local, context or usability
requirements. When non-hexadecimal characters are desired at the requirements. When non-hexadecimal characters are desired at the
user interface layer such as when other printable US-ASCII characters user interface layer such as when other printable US-ASCII characters
or international characters are used, SASLprep [RFC4013] MUST be used or international characters are used, SASLprep [RFC4013] MUST be used
to normalize user input before converting it to a string of to normalize user input before converting it to a string of
hexadecimal characters. For example, if a given application allows hexadecimal characters. For example, if a given application allows
use of any printable US-ASCII characters and extended ASCII the use of any printable US-ASCII characters and extended ASCII
characters for Client ID and password fields and the Client ID is set characters for Client ID and Password fields, and the Client ID is
to "myclient!D" and associated password is set to "mYpas&#rD", the set to "myclient!D" and the associated Password is set to
user enters through the keyboard or other means a Client ID of "mYpas&#rD", the user enters through the keyboard or other means a
"myclient!D" and a password of "mYpas&#rD" in separate form fields or Client ID of "myclient!D" and a Password of "mYpas&#rD" in separate
as instructed by the provider. The application's layer processing form fields or as instructed by the provider. The application's
user input MUST then convert the values entered by the user to the layer processing user input MUST then convert the values entered by
following string for use in the protocol: the user to the following string for use in the protocol:
"1146D79636C69656E7421442126D5970617326237244" (note that in this "1146D79636C69656E7421442126D5970617326237244" (note that in this
example the Checksum TLV is not added). example the Checksum TLV is not added).
The example is explained further below in detail: The example is explained further below in detail:
Assume that the raw Client ID value or the value entered by the use Assume that the raw Client ID value or the value entered by the use
is: myclient!ID is: myclient!ID
The Client ID value as characters names is: The Client ID value as characters names is:
skipping to change at page 21, line 39 skipping to change at page 22, line 45
U+0044 LATIN CAPITAL LETTER D character U+0044 LATIN CAPITAL LETTER D character
The UTF-8 conversion of the Client ID value is: 6D 79 63 6C 69 65 6E The UTF-8 conversion of the Client ID value is: 6D 79 63 6C 69 65 6E
74 21 44 74 21 44
The length of the Client ID value in hexadecimal characters is: 14 The length of the Client ID value in hexadecimal characters is: 14
The TLV presentation of the Client ID field is: The TLV presentation of the Client ID field is:
1146D79636C69656E742144 1146D79636C69656E742144
The raw password value or the value entered by the user is: mYpas&#rD The raw Password value or the value entered by the user is: mYpas&#rD
The password value as character names is: The Password value as character names is:
U+006D LATIN SMALL LETTER M character U+006D LATIN SMALL LETTER M character
U+0059 LATIN LARGE LETTER Y character U+0059 LATIN LARGE LETTER Y character
U+0070 LATIN SMALL LETTER P character U+0070 LATIN SMALL LETTER P character
U+0061 LATIN SMALL LETTER A character U+0061 LATIN SMALL LETTER A character
U+0073 LATIN SMALL LETTER S character U+0073 LATIN SMALL LETTER S character
U+0026 AMPERSAND character (&) U+0026 AMPERSAND character (&)
U+0023 POUND SIGN character (#) U+0023 POUND SIGN character (#)
U+0072 LATIN SMALL LETTER R character U+0072 LATIN SMALL LETTER R character
U+0044 LATIN LARGE LETTER D character U+0044 LATIN LARGE LETTER D character
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3.4.1.2. User Authentication Data Calculation 3.4.1.2. User Authentication Data Calculation
The Authentication Data consists of a Client ID (extracted from the The Authentication Data consists of a Client ID (extracted from the
AC) and a value, which is derived from AC as follows (refer to AC) and a value, which is derived from AC as follows (refer to
Section 3.4.2 for a description of DSKPP-PRF in general and Section 3.4.2 for a description of DSKPP-PRF in general and
Appendix D for a description of DSKPP-PRF-AES): Appendix D for a description of DSKPP-PRF-AES):
MAC = DSKPP-PRF(K_AC, AC->ClientID||URL_S||R_C||[R_S], 16) MAC = DSKPP-PRF(K_AC, AC->ClientID||URL_S||R_C||[R_S], 16)
In four-pass DSKPP, the cryptographic module uses R_C, R_S, and URL_S In four-pass DSKPP, the cryptographic module uses R_C, R_S, and URL_S
to calculate the MAC, where URL_S is the URL the DSKPP client uses to calculate the MAC, where URL_S is the URL the DSKPP Client uses
when contacting the DSKPP server. In two-pass DSKPP, the when contacting the DSKPP Server. In two-pass DSKPP, the
cryptographic module does not have access to R_S, therefore only R_C cryptographic module does not have access to R_S, therefore only R_C
is used in combination with URL_S to produce the MAC. In either is used in combination with URL_S to produce the MAC. In either
case, K_AC MUST be derived from AC->password as follows [PKCS-5]: case, K_AC MUST be derived from AC->password as follows [PKCS-5]:
K_AC = PBKDF2(AC->password, R_C || K, iter_count, 16) K_AC = PBKDF2(AC->password, R_C || K, iter_count, 16)
One of the following values for K MUST be used: One of the following values for K MUST be used:
a. In four-pass: a. In four-pass:
* The public key of the DSKPP server (K_SERVER), or (in the pre- * The public key of the DSKPP Server (K_SERVER), or (in the pre-
shared key variant) the pre-shared key between the client and shared key variant) the pre-shared key between the client and
the server (K_SHARED) the server (K_SHARED).
b. In two-pass: b. In two-pass:
* The public key of the DSKPP client, or the public key of the * The public key of the DSKPP Client, or the public key of the
device when a device certificate is available device when a device certificate is available.
* The pre-shared key between the client and the server * The pre-shared key between the client and the server
(K_SHARED) (K_SHARED).
* A passphrase-derived key * A passphrase-derived key.
The iteration count, iter_count, MUST be set to at least 100,000 The iteration count, iter_count, MUST be set to at least 100,000
except in the last two two-pass cases (where K is set to K_SHARED or except in the last two two-pass cases (where K is set to K_SHARED or
a passphrase-derived key), in which case iter_count MUST be set to 1. a passphrase-derived key), in which case iter_count MUST be set to 1.
3.4.2. The DSKPP One-Way Pseudorandom Function, DSKPP-PRF 3.4.2. The DSKPP One-Way Pseudorandom Function, DSKPP-PRF
Regardless of the protocol variant employed, there is a requirement Regardless of the protocol variant employed, there is a requirement
for a cryptographic primitive that provides a deterministic for a cryptographic primitive that provides a deterministic
transformation of a secret key k and a varying length octet string s transformation of a secret key k and a varying length octet string s
to a bit string of specified length dsLen. to a bit string of specified length dsLen.
This primitive must meet the same requirements as for a keyed hash This primitive must meet the same requirements as for a keyed hash
function: It MUST take an arbitrary length input, and generate an function: it MUST take an arbitrary length input and generate an
output that is one-way and collision-free (for a definition of these output that is one way and collision free (for a definition of these
terms, see, e.g., [FAQ]). Further, its output MUST be unpredictable terms, see, e.g., [FAQ]). Further, its output MUST be unpredictable
even if other outputs for the same key are known. even if other outputs for the same key are known.
From the point of view of this specification, DSKPP-PRF is a "black- From the point of view of this specification, DSKPP-PRF is a "black-
box" function that, given the inputs, generates a pseudorandom value box" function that, given the inputs, generates a pseudorandom value
and MAY be realized by any appropriate and competent cryptographic and MAY be realized by any appropriate and competent cryptographic
technique. Appendix D contains two example realizations of DSKPP- technique. Appendix D contains two example realizations of DSKPP-
PRF. PRF.
DSKPP-PRF(k, s, dsLen) DSKPP-PRF(k, s, dsLen)
Input: Input:
k secret key in octet string format k secret key in octet string format
s octet string of varying length consisting of variable data s octet string of varying length consisting of variable data
distinguishing the particular string being derived distinguishing the particular string being derived
dsLen desired length of the output dsLen desired length of the output
Output: Output:
DS pseudorandom string, dsLen-octets long DS pseudorandom string, dsLen octets long
For the purposes of this document, the secret key k MUST be at least For the purposes of this document, the secret key k MUST be at least
16 octets long. 16 octets long.
3.4.3. The DSKPP Message Hash Algorithm 3.4.3. The DSKPP Message Hash Algorithm
When sending its last message in a protocol run, the DSKPP server When sending its last message in a protocol run, the DSKPP Server
generates a MAC that is used by the client for key confirmation. generates a MAC that is used by the client for key confirmation.
Computation of the MAC MUST include a hash of all DSKPP messages sent Computation of the MAC MUST include a hash of all DSKPP messages sent
by the client and server during the transaction. To compute a by the client and server during the transaction. To compute a
message hash for the MAC given a sequence of DSKPP messages msg_1, message hash for the MAC given a sequence of DSKPP messages msg_1,
..., msg_n, the following operations MUST be carried out: ..., msg_n, the following operations MUST be carried out:
a. The sequence of messages contains all DSKPP Request and Response a. The sequence of messages contains all DSKPP Request and Response
messages up to but not including this message. messages up to but not including this message.
b. Re-transmitted messages are removed from the sequence of b. Re-transmitted messages are removed from the sequence of
messages. messages.
skipping to change at page 24, line 23 skipping to change at page 25, line 23
[FIPS180-SHA]. [FIPS180-SHA].
4. Four-Pass Protocol Usage 4. Four-Pass Protocol Usage
This section describes the methods and message flow that comprise the This section describes the methods and message flow that comprise the
four-pass protocol variant. Four-pass DSKPP depends on a client- four-pass protocol variant. Four-pass DSKPP depends on a client-
server key agreement mechanism. server key agreement mechanism.
4.1. The Key Agreement Mechanism 4.1. The Key Agreement Mechanism
With 4-pass DSKPP, the symmetric key that is the target of With four-pass DSKPP, the symmetric key that is the target of
provisioning, is generated on-the-fly without being transferred provisioning, is generated on-the-fly without being transferred
between the DSKPP client and DSKPP server. The data flow and between the DSKPP Client and DSKPP Server. The data flow and
computation are described below. computation are described below.
4.1.1. Data Flow 4.1.1. Data Flow
A sample data flow showing key generation during the 4-pass protocol A sample data flow showing key generation during the four-pass
is shown in Figure 3. protocol is shown in Figure 3.
+----------------------+ +----------------------+ +----------------------+ +----------------------+
| +------------+ | | | | +------------+ | | |
| | Server key | | | | | | Server key | | | |
| +<-| Public |------>------------->-------------+---------+ | | +<-| Public |------>------------->-------------+---------+ |
| | | Private | | | | | | | | | Private | | | | | |
| | +------------+ | | | | | | | +------------+ | | | | |
| | | | | | | | | | | | | | | |
| V V | | V V | | V V | | V V |
| | +---------+ | | +---------+ | | | | +---------+ | | +---------+ | |
skipping to change at page 25, line 38 skipping to change at page 26, line 38
| V | | V | | V | | V |
| +-------+ | | +-------+ | | +-------+ | | +-------+ |
| | Key | | | | Key | | | | Key | | | | Key | |
| +-------+ | | +-------+ | | +-------+ | | +-------+ |
| +-------+ | | +-------+ | | +-------+ | | +-------+ |
| |Key Id |-------->------------->------|Key Id | | | |Key Id |-------->------------->------|Key Id | |
| +-------+ | | +-------+ | | +-------+ | | +-------+ |
+----------------------+ +----------------------+ +----------------------+ +----------------------+
DSKPP Server DSKPP Client DSKPP Server DSKPP Client
Figure 3: Principal data flow for DSKPP key generation - Figure 3: Principal Data Flow for DSKPP Key Generation Using Public
using public server key Server Key
The inclusion of the two random nonces (R_S and R_C) in the key The inclusion of the two random nonces (R_S and R_C) in the key
generation provides assurance to both sides (the cryptographic module generation provides assurance to both sides (the cryptographic module
and the DSKPP server) that they have contributed to the key's and the DSKPP Server) that they have contributed to the key's
randomness and that the key is unique. The inclusion of the randomness and that the key is unique. The inclusion of the
encryption key (K) ensures that no man-in-the-middle may be present, encryption key (K) ensures that no man in the middle may be present,
or else the cryptographic module will end up with a key different or else the cryptographic module will end up with a key different
from the one stored by the legitimate DSKPP server. from the one stored by the legitimate DSKPP Server.
Conceptually, although R_C is one pseudorandom string, it may be Conceptually, although R_C is one pseudorandom string, it may be
viewed as consisting of two components, R_C1 and R_C2, where R_C1 is viewed as consisting of two components, R_C1 and R_C2, where R_C1 is
generated during the protocol run, and R_C2 can be pre-generated and generated during the protocol run, and R_C2 can be pre-generated and
loaded on the cryptographic module before the device is issued to the loaded on the cryptographic module before the device is issued to the
user. In that case, the latter string, R_C2, SHOULD be unique for user. In that case, the latter string, R_C2, SHOULD be unique for
each cryptographic module. each cryptographic module.
A man-in-the-middle (in the form of corrupt client software or a A man in the middle (in the form of corrupt client software or a
mistakenly contacted server) may present his own public key to the mistakenly contacted server) may present his own public key to the
cryptographic module. This will enable the attacker to learn the cryptographic module. This will enable the attacker to learn the
client's version of K_TOKEN. However, the attacker is not able to client's version of K_TOKEN. However, the attacker is not able to
persuade the legitimate server to derive the same value for K_TOKEN, persuade the legitimate server to derive the same value for K_TOKEN,
since K_TOKEN is a function of the public key involved, and the since K_TOKEN is a function of the public key involved, and the
attacker's public key must be different than the correct server's (or attacker's public key must be different than the correct server's (or
else the attacker would not be able to decrypt the information else the attacker would not be able to decrypt the information
received from the client). Therefore, once the attacker is no longer received from the client). Therefore, once the attacker is no longer
"in the middle," the client and server will detect that they are "out "in the middle," the client and server will detect that they are "out
of sync" when they try to use their keys. In the case of encrypting of sync" when they try to use their keys. In the case of encrypting
R_C with K_SERVER, it is therefore important to verify that K_SERVER R_C with K_SERVER, it is therefore important to verify that K_SERVER
really is the legitimate server's key. One way to do this is to really is the legitimate server's key. One way to do this is to
independently validate a newly generated K_TOKEN against some independently validate a newly generated K_TOKEN against some
validation service at the server (e.g., using a connection validation service at the server (e.g., using a connection
independent from the one used for the key generation). independent from the one used for the key generation).
4.1.2. Computation 4.1.2. Computation
In 4-pass DSKPP, the client and server both generate K_TOKEN and In four-pass DSKPP, the client and server both generate K_TOKEN and
K_MAC by deriving them from a provisioning key (K_PROV) using the K_MAC by deriving them from a provisioning key (K_PROV) using the
DSKPP-PRF function (refer to Section 3.4.2) as follows: DSKPP-PRF (refer to Section 3.4.2) as follows:
K_PROV = DSKPP-PRF(k,s,dsLen), where K_PROV = DSKPP-PRF(k,s,dsLen), where
k = R_C (i.e., the secret random value chosen by the DSKPP k = R_C (i.e., the secret random value chosen by the DSKPP
client) Client)
s = "Key generation" || K || R_S (where K is the key used to s = "Key generation" || K || R_S (where K is the key used to
encrypt R_C and R_S is the random value chosen by the DSKPP encrypt R_C and R_S is the random value chosen by the DSKPP
server) Server)
dsLen = (desired length of K_PROV whose first half constitutes dsLen = (desired length of K_PROV whose first half constitutes
K_MAC and second half constitutes K_TOKEN) K_MAC and second half constitutes K_TOKEN)
Then K_TOKEN and K_MAC are derived from K_PROV, where Then, K_TOKEN and K_MAC are derived from K_PROV, where
K_PROV = K_MAC || K_TOKEN K_PROV = K_MAC || K_TOKEN
When computing K_PROV, the derived keys, K_MAC and K_TOKEN, MAY be When computing K_PROV, the derived keys, K_MAC and K_TOKEN, MAY be
subject to an algorithm-dependent transform before being adopted as a subject to an algorithm-dependent transform before being adopted as a
key of the selected type. One example of this is the need for parity key of the selected type. One example of this is the need for parity
in DES keys. in DES keys.
Note that this computation pertains to 4-pass DSKPP only. Note that this computation pertains to four-pass DSKPP only.
4.2. Message Flow 4.2. Message Flow
The four-pass protocol flow consists of two message exchanges: The four-pass protocol flow consists of two message exchanges:
1: Pass 1 = <KeyProvClientHello>, Pass 2 = <KeyProvServerHello> 1: Pass 1 = <KeyProvClientHello>, Pass 2 = <KeyProvServerHello>
2: Pass 3 = <KeyProvClientNonce>, Pass 4 = <KeyProvServerFinished> 2: Pass 3 = <KeyProvClientNonce>, Pass 4 = <KeyProvServerFinished>
The first pair of messages negotiate cryptographic algorithms and The first pair of messages negotiate cryptographic algorithms and
exchange nonces. The second pair of messages establishes a symmetric exchange nonces. The second pair of messages establishes a symmetric
key using mutually authenticated key agreement. key using mutually authenticated key agreement.
skipping to change at page 27, line 26 skipping to change at page 28, line 26
format and examples are in Section 8 and Appendix B. format and examples are in Section 8 and Appendix B.
4.2.1. KeyProvTrigger 4.2.1. KeyProvTrigger
DSKPP Client DSKPP Server DSKPP Client DSKPP Server
------------ ------------ ------------ ------------
[<---] AD, [DeviceID], [<---] AD, [DeviceID],
[KeyID], [URL_S] [KeyID], [URL_S]
When this message is sent: When this message is sent:
The "trigger" message is optional. The DSKPP server sends this The "trigger" message is optional. The DSKPP Server sends this
message after the following out-of-band steps are performed: message after the following out-of-band steps are performed:
1. A user directed their browser to a key provisioning web 1. A user directed their browser to a key provisioning web
application and signs in (i.e., authenticates) application and signs in (i.e., authenticates).
2. The user requests a key 2. The user requests a key.
3. The web application processes the request and returns an 3. The web application processes the request and returns an
authentication code to the user, e.g., in response to an Authentication Code to the user, e.g., in response to an
enrollment request via a secure web session enrollment request via a secure web session.
4. The web application retrieves the authentication code from the 4. The web application retrieves the Authentication Code from the
user (possibly by asking the user to enter it using a web user (possibly by asking the user to enter it using a web
form, or alternatively by the user selecting a URL in which form, or alternatively by the user selecting a URL in which
the authentication code is embedded) the Authentication Code is embedded).
5. The web application derives authentication data (AD) from the 5. The web application derives Authentication Data (AD) from the
authentication code as described in Section 3.4.1 Authentication Code as described in Section 3.4.1.
6. The web application passes AD, and possibly a DeviceID 6. The web application passes AD, and possibly a DeviceID
(identifies a particular device to which the key is to be (identifies a particular device to which the key is to be
provisioned) and/or KeyID (identifies a key that will be provisioned) and/or KeyID (identifies a key that will be
replaced) to the DSKPP server replaced) to the DSKPP Server.
Purpose of this message: Purpose of this message:
To start a DSKPP session: The DSKPP server uses this message to To start a DSKPP session: The DSKPP Server uses this message to
trigger a client-side application to send the first DSKPP message. trigger a client-side application to send the first DSKPP message.
To provide a way for the key provisioning system to get the DSKPP To provide a way for the key provisioning system to get the DSKPP
server URL to the DSKPP client. Server URL to the DSKPP Client.
So the key provisioning system can point the DSKPP client to a So the key provisioning system can point the DSKPP Client to a
particular cryptographic module that was pre-configured in the particular cryptographic module that was pre-configured in the
DSKPP provisioning server. DSKPP provisioning server.
In the case of key renewal, to identify the key to be replaced. In the case of key renewal, to identify the key to be replaced.
What is contained in this message: What is contained in this message:
AD MUST be provided to allow the DSKPP server to authenticate the AD MUST be provided to allow the DSKPP Server to authenticate the
user before completing the protocol run. user before completing the protocol run.
A DeviceID MAY be included to allow a key provisioning application A DeviceID MAY be included to allow a key provisioning application
to bind the provisioned key to a specific device. to bind the provisioned key to a specific device.
A KeyID MAY be included to allow the key provisioning application A KeyID MAY be included to allow the key provisioning application
to identify a key to be replaced, e.g., in the case of key to identify a key to be replaced, e.g., in the case of key
renewal. renewal.
The Server URL MAY be included to allow the key provisioning The Server URL MAY be included to allow the key provisioning
application to inform the DSKPP client of which server to contact application to inform the DSKPP Client of which server to contact.
4.2.2. KeyProvClientHello 4.2.2. KeyProvClientHello
DSKPP Client DSKPP Server DSKPP Client DSKPP Server
------------ ------------ ------------ ------------
SAL, [AD], SAL, [AD],
[DeviceID], [KeyID] ---> [DeviceID], [KeyID] --->
When this message is sent: When this message is sent:
When a DSKPP client first connects to a DSKPP server, it is When a DSKPP Client first connects to a DSKPP Server, it is
required to send the <KeyProvClientHello> as its first message. required to send the <KeyProvClientHello> as its first message.
The client can also send a <KeyProvClientHello> in response to a The client can also send a <KeyProvClientHello> in response to a
<KeyProvTrigger>. <KeyProvTrigger>.
What is contained in this message: What is contained in this message:
The Security Attribute List (SAL) included with The Security Attribute List (SAL) included with
<KeyProvClientHello> contains the combinations of DSKPP versions, <KeyProvClientHello> contains the combinations of DSKPP versions,
variants, key package formats, key types, and cryptographic variants, key package formats, key types, and cryptographic
algorithms that the DSKPP client supports in order of the client's algorithms that the DSKPP Client supports in order of the client's
preference (favorite choice first). preference (favorite choice first).
If <KeyProvClientHello> was preceded by a <KeyProvTrigger>, then If <KeyProvClientHello> was preceded by a <KeyProvTrigger>, then
this message MUST also include the Authentication (AD), DeviceID, this message MUST also include the Authentication Data (AD),
and/or KeyID that was provided with the trigger. DeviceID, and/or KeyID that was provided with the trigger.
If <KeyProvClientHello> was not preceded by a <KeyProvTrigger>, If <KeyProvClientHello> was not preceded by a <KeyProvTrigger>,
then this message MAY contain a device ID that was pre-shared with then this message MAY contain a DeviceID that was pre-shared with
the DSKPP server, and a key ID associated with a key previously the DSKPP Server, and a key ID associated with a key previously
provisioned by the DSKPP provisioning server. provisioned by the DSKPP provisioning server.
Application note: Application note:
If this message is preceded by trigger message <KeyProvTrigger>, If this message is preceded by trigger message <KeyProvTrigger>,
then the application will already have AD available (see then the application will already have AD available (see
Section 4.2.1). However, if this message was not preceded by Section 4.2.1). However, if this message was not preceded by
<KeyProvTrigger>, then the application MUST retrieve the user <KeyProvTrigger>, then the application MUST retrieve the User
authentication code, possibly by prompting the user to manually Authentication Code, possibly by prompting the user to manually
enter their authentication code, e.g., on a device with only a enter their Authentication Code, e.g., on a device with only a
numeric keypad. numeric keypad.
The application MUST also derive Authentication Data (AD) from the The application MUST also derive Authentication Data (AD) from the
authentication code, as described in Section 3.4.1, and save it Authentication Code, as described in Section 3.4.1, and save it
for use in its next message, <KeyProvClientNonce>. for use in its next message, <KeyProvClientNonce>.
How the DSKPP server uses this message: How the DSKPP Server uses this message:
The DSKPP server will look for an acceptable combination of DSKPP The DSKPP Server will look for an acceptable combination of DSKPP
version, variant (in this case, four-pass), key package format, version, variant (in this case, four-pass), key package format,
key type, and cryptographic algorithms. If the DSKPP Client's SAL key type, and cryptographic algorithms. If the DSKPP Client's SAL
does not match the capabilities of the DSKPP Server, or does not does not match the capabilities of the DSKPP Server, or does not
comply with key provisioning policy, then the DSKPP Server will comply with key provisioning policy, then the DSKPP Server will
set the Status attribute to something other than "Continue". set the Status attribute to something other than "Continue".
Otherwise, Status will be set to "Continue". Otherwise, the Status attribute will be set to "Continue".
If included in <KeyProvClientHello>, the DSKPP server will If included in <KeyProvClientHello>, the DSKPP Server will
validate the Authentication Data (AD), DeviceID, and KeyID. The validate the Authentication Data (AD), DeviceID, and KeyID. The
DSKPP server MUST NOT accept the DeviceID unless the server sent DSKPP Server MUST NOT accept the DeviceID unless the server sent
the DeviceID in a preceding trigger message. Note that it is also the DeviceID in a preceding trigger message. Note that it is also
legitimate for a DSKPP client to initiate the DSKPP protocol run legitimate for a DSKPP Client to initiate the DSKPP run without
without having received a <KeyProvTrigger> message from a server, having received a <KeyProvTrigger> message from a server, but in
but in this case any provided DeviceID MUST NOT be accepted by the this case any provided DeviceID MUST NOT be accepted by the DSKPP
DSKPP server unless the server has access to a unique key for the Server unless the server has access to a unique key for the
identified device and that key will be used in the protocol. identified device and that key will be used in the protocol.
4.2.3. KeyProvServerHello 4.2.3. KeyProvServerHello
DSKPP Client DSKPP Server DSKPP Client DSKPP Server
------------ ------------ ------------ ------------
<--- SAL, R_S, [K], [MAC] <--- SAL, R_S, [K], [MAC]
When this message is sent: When this message is sent:
The DSKPP server will send this message in response to a The DSKPP Server will send this message in response to a
<KeyProvClientHello> message after it looks for an acceptable <KeyProvClientHello> message after it looks for an acceptable
combination of DSKPP version, variant (in this case, four-pass), combination of DSKPP version, variant (in this case, four-pass),
key package format, key type, and set of cryptographic algorithms. key package format, key type, and set of cryptographic algorithms.
If it could not find an acceptable combination, then it will still If it could not find an acceptable combination, then it will still
send the message, but with a failure status. send the message, but with a failure status.
Purpose of this message: Purpose of this message:
With this message, the context for the protocol run is set. With this message, the context for the protocol run is set.
Furthermore, the DSKPP server uses this message to transmit a Furthermore, the DSKPP Server uses this message to transmit a
random nonce, which is required for each side to agree upon the random nonce, which is required for each side to agree upon the
same symmetric key (K_TOKEN). same symmetric key (K_TOKEN).
What is contained in this message: What is contained in this message:
A status attribute equivalent to the server's return code to A status attribute equivalent to the server's return code to
<KeyProvClientHello>. If the server found an acceptable set of <KeyProvClientHello>. If the server found an acceptable set of
attributes from the client's SAL, then it sets status to Continue attributes from the client's SAL, then it sets status to Continue
and returns an SAL (selected from the SAL that it received in and returns an SAL (selected from the SAL that it received in
<KeyProvClientHello>). The Server's SAL specifies the DSKPP <KeyProvClientHello>). The Server's SAL specifies the DSKPP
version and variant (in this case, four-pass), key type, version and variant (in this case, four-pass), key type,
skipping to change at page 30, line 30 skipping to change at page 31, line 31
A random nonce (R_S) for use in generating a symmetric key through A random nonce (R_S) for use in generating a symmetric key through
key agreement; the length of R_S may depend on the selected key key agreement; the length of R_S may depend on the selected key
type. type.
A key (K) for the DSKPP Client to use for encrypting the client A key (K) for the DSKPP Client to use for encrypting the client
nonce included with <KeyProvClientNonce>. K represents the nonce included with <KeyProvClientNonce>. K represents the
server's public key (K_SERVER) or a pre-shared secret key server's public key (K_SERVER) or a pre-shared secret key
(K_SHARED). (K_SHARED).
A MAC MUST be present if a key is being renewed so that the DSKPP A MAC MUST be present if a key is being renewed so that the DSKPP
client can confirm that the replacement key came from a trusted Client can confirm that the replacement key came from a trusted
server. This MAC MUST be computed using DSKPP-PRF (see server. This MAC MUST be computed using DSKPP-PRF (see
Section 3.4.2), where the input parameter k MUST be set to the Section 3.4.2), where the input parameter k MUST be set to the
existing MAC key K_MAC' (i.e., the value of the MAC key that existing MAC key K_MAC' (i.e., the value of the MAC key that
existed before this protocol run; the implementation MAY specify existed before this protocol run; the implementation MAY specify
K_MAC' to be the value of the K_TOKEN that is being replaced), and K_MAC' to be the value of the K_TOKEN that is being replaced), and
input parameter dsLen MUST be set to the length of R_S. input parameter dsLen MUST be set to the length of R_S.
How the DSKPP client uses this message: How the DSKPP Client uses this message:
When the Status attribute is not set to "Continue", this indicates When the Status attribute is not set to "Continue", this indicates
failure and the DSKPP client MUST abort the protocol. failure and the DSKPP Client MUST abort the protocol.
If successful execution of the protocol will result in the If successful execution of the protocol will result in the
replacement of an existing key with a newly generated one, the replacement of an existing key with a newly generated one, the
DSKPP client MUST verify the MAC provided in <KeyProvServerHello>. DSKPP Client MUST verify the MAC provided in <KeyProvServerHello>.
The DSKPP client MUST terminate the DSKPP session if the MAC does The DSKPP Client MUST terminate the DSKPP session if the MAC does
not verify, and MUST delete any nonces, keys, and/or secrets not verify, and MUST delete any nonces, keys, and/or secrets
associated with the failed run. associated with the failed run.
If Status is set to "Continue" the cryptographic module generates If the Status attribute is set to "Continue", the cryptographic
a random nonce (R_C) using the cryptographic algorithm specified module generates a random nonce (R_C) using the cryptographic
in the SAL. The length of the nonce R_C will depend on the algorithm specified in the SAL. The length of the nonce R_C will
selected key type. depend on the selected key type.
Encrypt R_C using K and the encryption algorithm included in the Encrypt R_C using K and the encryption algorithm included in the
SAL. SAL.
The method the DSKPP client MUST use to encrypt R_C: The method the DSKPP Client MUST use to encrypt R_C:
If K is equivalent to K_SERVER (i.e., the public key of the DSKPP If K is equivalent to K_SERVER (i.e., the public key of the DSKPP
server), then an RSA encryption scheme from PKCS #1 [PKCS-1] MAY Server), then an RSA encryption scheme from PKCS #1 [PKCS-1] MAY
be used. If K is equivalent to K_SERVER, then the cryptographic be used. If K is equivalent to K_SERVER, then the cryptographic
module SHOULD verify the server's certificate before using it to module SHOULD verify the server's certificate before using it to
encrypt R_C as described in [RFC2818], Section 3.1, and [RFC5280]. encrypt R_C as described in [RFC2818], Section 3.1, and [RFC5280].
If K is equivalent to K_SHARED, the DSKPP client MAY use the If K is equivalent to K_SHARED, the DSKPP Client MAY use the
DSKPP-PRF function to avoid dependence on other algorithms. In DSKPP-PRF to avoid dependence on other algorithms. In this case,
this case, the client uses K_SHARED as input parameter k (K_SHARED the client uses K_SHARED as input parameter k (K_SHARED SHOULD be
SHOULD be used solely for this purpose) as follows: used solely for this purpose) as follows:
dsLen = len(R_C), where "len" is the length of R_C dsLen = len(R_C), where "len" is the length of R_C
DS = DSKPP-PRF(K_SHARED, "Encryption" || R_S, dsLen) DS = DSKPP-PRF(K_SHARED, "Encryption" || R_S, dsLen)
This will produce a pseudorandom string DS of length equal to R_C. This will produce a pseudorandom string DS of length equal to R_C.
Encryption of R_C MAY then be achieved by XOR-ing DS with R_C: Encryption of R_C MAY then be achieved by XOR-ing DS with R_C:
E(DS, R_C) = DS ^ R_C E(DS, R_C) = DS ^ R_C
The DSKPP server will then perform the reverse operation to The DSKPP Server will then perform the reverse operation to
extract R_C from E(DS, R_C). extract R_C from E(DS, R_C).
4.2.4. KeyProvClientNonce 4.2.4. KeyProvClientNonce
DSKPP Client DSKPP Server DSKPP Client DSKPP Server
------------ ------------ ------------ ------------
E(K,R_C), AD ---> E(K,R_C), AD --->
When this message is sent: When this message is sent:
The DSKPP client will send this message immediately following a The DSKPP Client will send this message immediately following a
<KeyProvServerHello> message whose status was set to "Continue". <KeyProvServerHello> message whose status was set to "Continue".
Purpose of this message: Purpose of this message:
With this message the DSKPP client transmits user authentication With this message the DSKPP Client transmits User Authentication
data (AD) and a random nonce encrypted with the DSKPP server's key Data (AD) and a random nonce encrypted with the DSKPP Server's key
(K). The client's random nonce is required for each side to agree (K). The client's random nonce is required for each side to agree
upon the same symmetric key (K_TOKEN). upon the same symmetric key (K_TOKEN).
What is contained in this message: What is contained in this message:
Authentication Data (AD) that was derived from an authentication Authentication Data (AD) that was derived from an Authentication
code entered by the user before <KeyProvClientHello> was sent Code entered by the user before <KeyProvClientHello> was sent
(refer to Section 3.2). (refer to Section 3.2).
The DSKPP client's random nonce (R_C), which was encrypted as The DSKPP Client's random nonce (R_C), which was encrypted as
described in Section 4.2.3. described in Section 4.2.3.
How the DSKPP server uses this message: How the DSKPP Server uses this message:
The DSKPP server MUST use AD to authenticate the user. If The DSKPP Server MUST use AD to authenticate the user. If
authentication fails, then the DSKPP server MUST set the return authentication fails, then the DSKPP Server MUST set the return
code to a failure status. code to a failure status.
If user authentication passes, the DSKPP server decrypts R_C using If user authentication passes, the DSKPP Server decrypts R_C using
its key (K). The decryption method is based on whether K that was its key (K). The decryption method is based on whether K that was
transmitted to the client in <KeyProvServerHello> was equal to the transmitted to the client in <KeyProvServerHello> was equal to the
server's public key (K_SERVER) or a pre-shared key (K_SHARED) server's public key (K_SERVER) or a pre-shared key (K_SHARED)
(refer to Section 4.2.3 for a description of how the DSKPP client (refer to Section 4.2.3 for a description of how the DSKPP Client
encrypts R_C). encrypts R_C).
After extracting R_C, the DSKPP server computes K_TOKEN using a After extracting R_C, the DSKPP Server computes K_TOKEN using a
combination of the two random nonces R_S and R_C and its combination of the two random nonces R_S and R_C and its
encryption key, K, as described in Section 4.1.2. The particular encryption key, K, as described in Section 4.1.2. The particular
realization of DSKPP-PRF (e.g., those defined in Appendix D) realization of DSKPP-PRF (e.g., those defined in Appendix D)
depends on the MAC algorithm contained in the <KeyProvServerHello> depends on the MAC algorithm contained in the <KeyProvServerHello>
message. The DSKPP server then generates a key package that message. The DSKPP Server then generates a key package that
contains key usage attributes such as expiry date and length. The contains key usage attributes such as expiry date and length. The
key package MUST NOT include K_TOKEN since in the four-pass key package MUST NOT include K_TOKEN since in the four-pass
variant K_TOKEN is never transmitted between the DSKPP server and variant K_TOKEN is never transmitted between the DSKPP Server and
client. The server stores K_TOKEN and the key package with the Client. The server stores K_TOKEN and the key package with the
user's account on the cryptographic server. user's account on the cryptographic server.
Finally, the server generates a key confirmation MAC that the Finally, the server generates a key confirmation MAC that the
client will use to avoid a false "Commit" message that would cause client will use to avoid a false "Commit" message that would cause
the cryptographic module to end up in state in which the server the cryptographic module to end up in state in which the server
does not recognize the stored key. does not recognize the stored key.
The MAC used for key confirmation MUST be calculated as follows: The MAC used for key confirmation MUST be calculated as follows:
msg_hash = SHA-256(msg_1, ..., msg_n) msg_hash = SHA-256(msg_1, ..., msg_n)
dsLen = len(msg_hash) dsLen = len(msg_hash)
MAC = DSKPP-PRF (K_MAC, "MAC 1 computation" || msg_hash, dsLen) MAC = DSKPP-PRF (K_MAC, "MAC 1 computation" || msg_hash, dsLen)
where where
MAC The DSKPP Pseudo-Random Function defined in Section 3.4.2 is MAC The DSKPP Pseudorandom Function defined in Section 3.4.2 is
used to compute the MAC. The particular realization of DSKPP- used to compute the MAC. The particular realization of DSKPP-
PRF (e.g., those defined in Appendix D) depends on the MAC PRF (e.g., those defined in Appendix D) depends on the MAC
algorithm contained in the <KeyProvServerHello> message. The algorithm contained in the <KeyProvServerHello> message. The
MAC MUST be computed using the existing MAC key (K_MAC), and a MAC MUST be computed using the existing MAC key (K_MAC), and a
string that is formed by concatenating the (ASCII) string "MAC string that is formed by concatenating the (ASCII) string "MAC
1 computation" and a msg_hash 1 computation" and a msg_hash.
K_MAC The key derived from K_PROV, as described in Section 4.1.2. K_MAC The key derived from K_PROV, as described in Section 4.1.2.
msg_hash The message hash (defined in Section 3.4.3) of messages msg_hash The message hash (defined in Section 3.4.3) of messages
msg_1, ..., msg_n. msg_1, ..., msg_n.
4.2.5. KeyProvServerFinished 4.2.5. KeyProvServerFinished
DSKPP Client DSKPP Server DSKPP Client DSKPP Server
------------ ------------ ------------ ------------
<--- KP, MAC <--- KP, MAC
When this message is sent: When this message is sent:
The DSKPP server will send this message after authenticating the The DSKPP Server will send this message after authenticating the
user and, if authentication passed, generating K_TOKEN and a key user and, if authentication passed, generating K_TOKEN and a key
package, and associating them with the user's account on the package, and associating them with the user's account on the
cryptographic server. cryptographic server.
Purpose of this message: Purpose of this message:
With this message the DSKPP server confirms generation of the key With this message, the DSKPP Server confirms generation of the key
(K_TOKEN), and transmits the associated identifier and (K_TOKEN) and transmits the associated identifier and application-
application-specific attributes, but not the key itself, in a key specific attributes, but not the key itself, in a key package to
package to the client for protocol completion. the client for protocol completion.
What is contained in this message: What is contained in this message:
A status attribute equivalent to the server's return code to A status attribute equivalent to the server's return code to
<KeyProvClientNonce>. If user authentication passed, and the <KeyProvClientNonce>. If user authentication passed, and the
server successfully computed K_TOKEN, generated a key package, and server successfully computed K_TOKEN, generated a key package, and
associated them with the user's account on the cryptographic associated them with the user's account on the cryptographic
server, then it sets Status to Success. server, then it sets the Status attribute to "Success".
If the Status attribute is set to "Success", then this message
If status is Success, then this message acts as a "commit" acts as a "Commit" message, instructing the cryptographic module
message, instructing the cryptographic module to store the to store the generated key (K_TOKEN) and associate the given key
generated key (K_TOKEN) and associate the given key identifier identifier with this key. As such, a key package (KP) MUST be
with this key. As such, a key package (KP) MUST be included in included in this message, which holds an identifier for the
this message, which holds an identifier for the generated key (but generated key (but not the key itself) and additional
not the key itself) and additional configuration, e.g., the configuration, e.g., the identity of the DSKPP Server, key usage
identity of the DSKPP server, key usage attributes, etc. The attributes, etc. The default symmetric key package format MUST be
default symmetric key package format MUST be based on the Portable based on the Portable Symmetric Key Container (PSKC) defined in
Symmetric Key Container (PSKC) defined in [PSKC]. Alternative [RFC6030]. Alternative formats MAY include [RFC6031], PKCS #12
formats MAY include [SKPC-ASN.1], PKCS#12 [PKCS-12], or PKCS#5 XML [PKCS-12], or PKCS #5 XML [PKCS-5-XML] format.
[PKCS-5-XML] format.
With KP, the server includes a key confirmation MAC that the With KP, the server includes a key confirmation MAC that the
client uses to avoid a false "Commit". The MAC algorithm is the client uses to avoid a false "Commit" message. The MAC algorithm
same DSKPP-PRF that was sent in the <KeyProvServerHello> message. is the same DSKPP-PRF that was sent in the <KeyProvServerHello>
message.
How the DSKPP client uses this message:
How the DSKPP Client uses this message:
When the Status attribute is not set to "Success", this indicates When the Status attribute is not set to "Success", this indicates
failure and the DSKPP client MUST abort the protocol. failure and the DSKPP Client MUST abort the protocol.
After receiving a <KeyProvServerFinished> message with Status = After receiving a <KeyProvServerFinished> message with Status =
"Success", the DSKPP client MUST verify the key confirmation MAC "Success", the DSKPP Client MUST verify the key confirmation MAC
that was transmitted with this message. The DSKPP client MUST that was transmitted with this message. The DSKPP Client MUST
terminate the DSKPP session if the MAC does not verify, and MUST, terminate the DSKPP session if the MAC does not verify, and MUST,
in this case, also delete any nonces, keys, and/or secrets in this case, also delete any nonces, keys, and/or secrets
associated with the failed run of the protocol. associated with the failed run of the protocol.
If <KeyProvServerFinished> has Status = "Success" and the MAC was If <KeyProvServerFinished> has Status = "Success", and the MAC was
verified, then the DSKPP client MUST calculate K_TOKEN from the verified, then the DSKPP Client MUST calculate K_TOKEN from the
combination of the two random nonces R_S and R_C and the server's combination of the two random nonces R_S and R_C and the server's
encryption key, K, as described in Section 4.1.2. The DSKPP-PRF encryption key, K, as described in Section 4.1.2. The DSKPP-PRF
is the same one used for MAC computation. The DSKPP client is the same one used for MAC computation. The DSKPP Client
associates the key package contained in <KeyProvServerFinished> associates the key package contained in <KeyProvServerFinished>
with the generated key, K_TOKEN, and stores this data permanently with the generated key, K_TOKEN, and stores this data permanently
on the cryptographic module. on the cryptographic module.
After this operation, it MUST NOT be possible to overwrite the key After this operation, it MUST NOT be possible to overwrite the key
unless knowledge of an authorizing key is proven through a MAC on unless knowledge of an authorizing key is proven through a MAC on
a later <KeyProvServerHello> (and <KeyProvServerFinished>) a later <KeyProvServerHello> (and <KeyProvServerFinished>)
message. message.
5. Two-Pass Protocol Usage 5. Two-Pass Protocol Usage
This section describes the methods and message flow that comprise the This section describes the methods and message flow that comprise the
two-pass protocol variant. Two-pass DSKPP is essentially a transport two-pass protocol variant. Two-pass DSKPP is essentially a transport
of keying material from the DSKPP server to the DSKPP client. The of keying material from the DSKPP Server to the DSKPP Client. The
DSKPP server transmits keying material in a key package formatted in DSKPP Server transmits keying material in a key package formatted in
accordance with [PSKC], [SKPC-ASN.1], PKCS#12 [PKCS-12], or PKCS#5 accordance with [RFC6030], [RFC6031], PKCS #12 [PKCS-12], or PKCS #5
XML [PKCS-5-XML]. XML [PKCS-5-XML].
The keying material includes a provisioning master key, K_PROV, from The keying material includes a provisioning master key, K_PROV, from
which the DSKPP client derives two keys: the symmetric key to be which the DSKPP Client derives two keys: the symmetric key to be
established in the cryptographic module, K_TOKEN, and a key, K_MAC, established in the cryptographic module, K_TOKEN, and a key, K_MAC,
used for key confirmation. The keying material also includes key used for key confirmation. The keying material also includes key
usage attributes, such as expiry date and length. usage attributes, such as expiry date and length.
The DSKPP server encrypts K_PROV to ensure that it is not exposed to The DSKPP Server encrypts K_PROV to ensure that it is not exposed to
any other entity than the DSKPP server and the cryptographic module any other entity than the DSKPP Server and the cryptographic module
itself. The DSKPP server uses any of three key protection methods to itself. The DSKPP Server uses any of three key protection methods to
encrypt K_PROV: Key Transport, Key Wrap, and Passphrase-Based Key encrypt K_PROV: Key Transport, Key Wrap, and Passphrase-Based Key
Wrap Key Protection Methods. Wrap Key Protection methods.
While the DSKPP client and server may negotiate the key protection While the DSKPP Client and server may negotiate the key protection
method to use, the actual key protection is carried out in the method to use, the actual key protection is carried out in the
KeyPackage. The format of a KeyPackage specifies how a key should be KeyPackage. The format of a KeyPackage specifies how a key should be
protected using the three key protection methods. The following protected using the three key protection methods. The following
KeyPackage formats are defined for DSKPP: KeyPackage formats are defined for DSKPP:
o PSKC Key Container [PSKC] at o PSKC Key Container [RFC6030] at
urn:ietf:params:xml:ns:keyprov:dskpp:pskc-key-container urn:ietf:params:xml:ns:keyprov:dskpp:pskc-key-container
o SKPC Key Container [SKPC-ASN.1] at o SKPC Key Container [RFC6031] at
urn:ietf:params:xml:ns:keyprov:dskpp:skpc-key-container urn:ietf:params:xml:ns:keyprov:dskpp:skpc-key-container
o PKCS12 Key Container [PKCS-12] at o PKCS12 Key Container [PKCS-12] at
urn:ietf:params:xml:ns:keyprov:dskpp:pkcs12-key-container urn:ietf:params:xml:ns:keyprov:dskpp:pkcs12-key-container
o PKCS5-XML Key Container [PKCS-5-XML] at o PKCS5-XML Key Container [PKCS-5-XML] at
urn:ietf:params:xml:ns:keyprov:dskpp:pkcs5-xml-key-container urn:ietf:params:xml:ns:keyprov:dskpp:pkcs5-xml-key-container
Each of the key protection methods is described below. Each of the key protection methods is described below.
5.1. Key Protection Methods 5.1. Key Protection Methods
This section introduces three key protection methods for the two-pass This section introduces three key protection methods for the two-pass
variant. Additional methods MAY be defined by external entities or variant. Additional methods MAY be defined by external entities or
through the IETF process. through the IETF process.
5.1.1. Key Transport 5.1.1. Key Transport
Purpose of this method: Purpose of this method:
This method is intended for PKI-capable devices. The DSKPP server This method is intended for PKI-capable devices. The DSKPP Server
encrypts keying material and transports it to the DSKPP client. encrypts keying material and transports it to the DSKPP Client.
The server encrypts the keying material using the public key of The server encrypts the keying material using the public key of
the DSKPP client, whose private key part resides in the the DSKPP Client, whose private key part resides in the
cryptographic module. The DSKPP client decrypts the keying cryptographic module. The DSKPP Client decrypts the keying
material and uses it to derive the symmetric key, K_TOKEN. material and uses it to derive the symmetric key, K_TOKEN.
This method is identified with the following URN: This method is identified with the following URN:
urn:ietf:params:xml:schema:keyprov:dskpp:transport urn:ietf:params:xml:schema:keyprov:dskpp:transport
The DSKPP server and client MUST support the following mechanism: The DSKPP Server and Client MUST support the following mechanism:
http://www.w3.org/2001/04/xmlenc#rsa-1_5 encryption mechanism http://www.w3.org/2001/04/xmlenc#rsa-1_5 encryption mechanism
defined in [XMLENC]. defined in [XMLENC].
5.1.2. Key Wrap 5.1.2. Key Wrap
Purpose of this method: Purpose of this method:
This method is ideal for pre-keyed devices, e.g., SIM cards. The This method is ideal for pre-keyed devices, e.g., SIM cards. The
DSKPP server encrypts keying material using a pre-shared key DSKPP Server encrypts keying material using a pre-shared key
wrapping key and transports it to the DSKPP client. The DSKPP wrapping key and transports it to the DSKPP Client. The DSKPP
client decrypts the keying material, and uses it to derive the Client decrypts the keying material, and uses it to derive the
symmetric key, K_TOKEN. symmetric key, K_TOKEN.
This method is identified with the following URN: This method is identified with the following URN:
urn:ietf:params:xml:schema:keyprov:dskpp:wrap urn:ietf:params:xml:schema:keyprov:dskpp:wrap
The DSKPP server and client MUST support all of the following key The DSKPP Server and Client MUST support all of the following key
wrapping mechanisms: wrapping mechanisms:
AES128 KeyWrap AES128 KeyWrap
Refer to id-aes128-wrap in [RFC3394] and Refer to id-aes128-wrap in [RFC3394] and
http://www.w3.org/2001/04/xmlenc#kw-aes128 in [XMLENC] http://www.w3.org/2001/04/xmlenc#kw-aes128 in [XMLENC]
AES128 KeyWrap with Padding AES128 KeyWrap with Padding
Refer to id-aes128-wrap-pad in [RFC5649] and Refer to id-aes128-wrap-pad in [RFC5649] and
http://www.w3.org/2001/04/xmlenc#kw-aes128 in [XMLENC] http://www.w3.org/2001/04/xmlenc#kw-aes128 in [XMLENC]
AES-CBC-128 AES-CBC-128
Refer to [FIPS197-AES] and Refer to [FIPS197-AES] and
http://www.w3.org/2001/04/xmlenc#aes128-cbc in [XMLENC] http://www.w3.org/2001/04/xmlenc#aes128-cbc in [XMLENC]
5.1.3. Passphrase-Based Key Wrap 5.1.3. Passphrase-Based Key Wrap
Purpose of this method: Purpose of this method:
This method is a variation of the Key Wrap Method that is This method is a variation of the Key Wrap Method that is
applicable to constrained devices with keypads, e.g., mobile applicable to constrained devices with keypads, e.g., mobile
phones. The DSKPP server encrypts keying material using a phones. The DSKPP Server encrypts keying material using a
wrapping key derived from a user-provided passphrase, and wrapping key derived from a user-provided passphrase, and
transports the encrypted material to the DSKPP client. The DSKPP transports the encrypted material to the DSKPP Client. The DSKPP
client decrypts the keying material, and uses it to derive the Client decrypts the keying material, and uses it to derive the
symmetric key, K_TOKEN. symmetric key, K_TOKEN.
To preserve the property of not exposing K_TOKEN to any other To preserve the property of not exposing K_TOKEN to any other
entity than the DSKPP server and the cryptographic module itself, entity than the DSKPP Server and the cryptographic module itself,
the method SHOULD be employed only when the device contains the method SHOULD be employed only when the device contains
facilities (e.g. a keypad) for direct entry of the passphrase. facilities (e.g., a keypad) for direct entry of the passphrase.
This method is identified with the following URN: This method is identified with the following URN:
urn:ietf:params:xml:schema:keyprov:dskpp:passphrase-wrap urn:ietf:params:xml:schema:keyprov:dskpp:passphrase-wrap
The DSKPP server and client MUST support the following: The DSKPP Server and Client MUST support the following:
* The PBES2 password-based encryption scheme defined in [PKCS-5] * The PBES2 password-based encryption scheme defined in [PKCS-5]
(and identified as (and identified as
http://www.rsasecurity.com/rsalabs/pkcs/schemas/pkcs-5#pbes2 in http://www.rsasecurity.com/rsalabs/pkcs/schemas/pkcs-5#pbes2 in
[PKCS-5-XML]) [PKCS-5-XML]).
* The PBKDF2 passphrase-based key derivation function also * The PBKDF2 passphrase-based key derivation function also
defined in [PKCS-5] (and identified as defined in [PKCS-5] (and identified as
http://www.rsasecurity.com/rsalabs/pkcs/schemas/pkcs-5#pbkdf2 http://www.rsasecurity.com/rsalabs/pkcs/schemas/pkcs-5#pbkdf2
in [PKCS-5-XML]) in [PKCS-5-XML]).
* All of the following key wrapping mechanisms: * All of the following key wrapping mechanisms:
AES128 KeyWrap AES128 KeyWrap
Refer to id-aes128-wrap in [RFC3394] and Refer to id-aes128-wrap in [RFC3394] and
http://www.w3.org/2001/04/xmlenc#kw-aes128 in [XMLENC] http://www.w3.org/2001/04/xmlenc#kw-aes128 in [XMLENC]
AES128 KeyWrap with Padding AES128 KeyWrap with Padding
Refer to id-aes128-wrap-pad in [RFC5649] and Refer to id-aes128-wrap-pad in [RFC5649] and
http://www.w3.org/2001/04/xmlenc#kw-aes128 in [XMLENC] http://www.w3.org/2001/04/xmlenc#kw-aes128 in [XMLENC]
AES-CBC-128 AES-CBC-128
Refer to [FIPS197-AES] and Refer to [FIPS197-AES] and
http://www.w3.org/2001/04/xmlenc#aes128-cbc in [XMLENC] http://www.w3.org/2001/04/xmlenc#aes128-cbc in [XMLENC]
5.2. Message Flow 5.2. Message Flow
The two-pass protocol flow consists of one exchange: The two-pass protocol flow consists of one exchange:
1: Pass 1 = <KeyProvClientHello>, Pass 2 = <KeyProvServerFinished> 1: Pass 1 = <KeyProvClientHello>, Pass 2 = <KeyProvServerFinished>
Although there is no exchange of the <ServerHello> message or the Although there is no exchange of the <ServerHello> message or the
<ClientNonce> message, the DSKPP client is still able to specify <ClientNonce> message, the DSKPP Client is still able to specify
algorithm preferences and supported key types in the algorithm preferences and supported key types in the
<KeyProvClientHello> message. <KeyProvClientHello> message.
The purpose and content of each message are described below. XML The purpose and content of each message are described below. XML
format and examples are in Section 8 and Appendix B. format and examples are in Section 8 and Appendix B.
5.2.1. KeyProvTrigger 5.2.1. KeyProvTrigger
The trigger message is used in exactly the same way for the two-pass The trigger message is used in exactly the same way for the two-pass
variant as for the four-pass variant; refer to Section 4.2.1. variant as for the four-pass variant; refer to Section 4.2.1.
5.2.2. KeyProvClientHello 5.2.2. KeyProvClientHello
DSKPP Client DSKPP Server DSKPP Client DSKPP Server
------------ ------------ ------------ ------------
SAL, AD, R_C, SAL, AD, R_C,
[DeviceID], [KeyID], [DeviceID], [KeyID],
KPML ---> KPML --->
When this message is sent: When this message is sent:
When a DSKPP Client first connects to a DSKPP Server, it is
When a DSKPP client first connects to a DSKPP server, it is
required to send the <KeyProvClientHello> as its first message. required to send the <KeyProvClientHello> as its first message.
The client can also send <KeyProvClientHello> in response to a The client can also send <KeyProvClientHello> in response to a
<KeyProvTrigger> message. <KeyProvTrigger> message.
Purpose of this message: Purpose of this message:
With this message, the DSKPP client specifies its algorithm With this message, the DSKPP Client specifies its algorithm
preferences and supported key types as well as which DSKPP preferences and supported key types as well as which DSKPP
versions, protocol variants (in this case "two-pass"), key package versions, protocol variants (in this case "two-pass"), key package
formats, and key protection methods that it supports. formats, and key protection methods that it supports.
Furthermore, the DSKPP client facilitates user authentication by Furthermore, the DSKPP Client facilitates user authentication by
transmitting the authentication data (AD) that was provided by the transmitting the Authentication Data (AD) that was provided by the
user before the first DSKPP message was sent. user before the first DSKPP message was sent.
Application note: Application note:
This message MUST send user authentication data (AD) to the DSKPP This message MUST send User Authentication Data (AD) to the DSKPP
server. If this message is preceded by trigger message Server. If this message is preceded by trigger message
<KeyProvTrigger>, then the application will already have AD <KeyProvTrigger>, then the application will already have AD
available (see Section 4.2.1). However, if this message was not available (see Section 4.2.1). However, if this message was not
preceded by <KeyProvTrigger>, then the application MUST retrieve preceded by <KeyProvTrigger>, then the application MUST retrieve
the user authentication code, possibly by prompting the user to the User Authentication Code, possibly by prompting the user to
manually enter their authentication code, e.g., on a device with manually enter their Authentication Code, e.g., on a device with
only a numeric keypad. The application MUST also derive only a numeric keypad. The application MUST also derive
Authentication Data (AD) from the authentication code, as Authentication Data (AD) from the Authentication Code, as
described in Section 3.4.1, and save it for use in its next described in Section 3.4.1, and save it for use in its next
message, <KeyProvClientNonce>. message, <KeyProvClientNonce>.
What is contained in this message: What is contained in this message:
The Security Attribute List (SAL) included with The Security Attribute List (SAL) included with
<KeyProvClientHello> contains the combinations of DSKPP versions, <KeyProvClientHello> contains the combinations of DSKPP versions,
variants, key package formats, key types, and cryptographic variants, key package formats, key types, and cryptographic
algorithms that the DSKPP client supports in order of the client's algorithms that the DSKPP Client supports in order of the client's
preference (favorite choice first). preference (favorite choice first).
Authentication Data (AD) that was either included with Authentication Data (AD) that was either included with
<KeyProvTrigger>, or generated as described in the "Application <KeyProvTrigger>, or generated as described in the "Application
Note" above Note" above.
The DSKPP client's random nonce (R_C), which was used by the The DSKPP Client's random nonce (R_C), which was used by the
client when generating AD. By inserting R_C into the DSKPP client when generating AD. By inserting R_C into the DSKPP
session, the DSKPP client is able to ensure the DSKPP server is session, the DSKPP Client is able to ensure the DSKPP Server is
live before committing the key. live before committing the key.
If <KeyProvClientHello> was preceded by a <KeyProvTrigger>, then If <KeyProvClientHello> was preceded by a <KeyProvTrigger>, then
this message MUST also include the DeviceID and/or KeyID that was this message MUST also include the DeviceID and/or KeyID that was
provided with the trigger. Otherwise, if a trigger message did provided with the trigger. Otherwise, if a trigger message did
not precede <KeyProvClientHello>, then this message MAY include a not precede <KeyProvClientHello>, then this message MAY include a
device ID that was pre-shared with the DSKPP server, and MAY DeviceID that was pre-shared with the DSKPP Server, and MAY
contain a key ID associated with a key previously provisioned by contain a key ID associated with a key previously provisioned by
the DSKPP provisioning server. the DSKPP provisioning server.
The list of key protection methods (KPML) that the DSKPP client The list of key protection methods (KPML) that the DSKPP Client
supports. Each item in the list MAY include an encryption key supports. Each item in the list MAY include an encryption key
"payload" for the DSKPP server to use to protect keying material "payload" for the DSKPP Server to use to protect keying material
that it sends back to the client. The payload MUST be of type that it sends back to the client. The payload MUST be of type
<ds:KeyInfoType> ([XMLDSIG]). For each key protection method, the <ds:KeyInfoType> ([XMLDSIG]). For each key protection method, the
allowable choices for <ds:KeyInfoType> are: allowable choices for <ds:KeyInfoType> are:
* Key Transport * Key Transport
Only those choices of <ds:KeyInfoType> that identify a public Only those choices of <ds:KeyInfoType> that identify a public
key (i.e., <ds:KeyName>, <ds:KeyValue>, <ds:X509Data>, or <ds: key (i.e., <ds:KeyName>, <ds:KeyValue>, <ds:X509Data>, or <ds:
PGPData>). The <ds:X509Certificate> option of the <ds: PGPData>). The <ds:X509Certificate> option of the <ds:
X509Data> alternative is RECOMMENDED when the public key X509Data> alternative is RECOMMENDED when the public key
corresponding to the private key on the cryptographic module corresponding to the private key on the cryptographic module
skipping to change at page 39, line 32 skipping to change at page 40, line 43
* Key Wrap * Key Wrap
Only those choices of <ds:KeyInfoType> that identify a Only those choices of <ds:KeyInfoType> that identify a
symmetric key (i.e., <ds:KeyName> and <ds:KeyValue>). The <ds: symmetric key (i.e., <ds:KeyName> and <ds:KeyValue>). The <ds:
KeyName> alternative is RECOMMENDED. KeyName> alternative is RECOMMENDED.
* Passphrase-Based Key Wrap * Passphrase-Based Key Wrap
The <ds:KeyName> option MUST be used and the key name MUST The <ds:KeyName> option MUST be used and the key name MUST
identify the passphrase that will be used by the server to identify the passphrase that will be used by the server to
generate the key wrapping key. The identifier and passphrase generate the key wrapping key. The identifier and passphrase
components of <ds:KeyName> MUST be set to the Client ID and components of <ds:KeyName> MUST be set to the Client ID and
authentication code components of AD (same AD as contained in Authentication Code components of AD (same AD as contained in
this message). this message).
How the DSKPP server uses this message: How the DSKPP Server uses this message:
The DSKPP server will look for an acceptable combination of DSKPP The DSKPP Server will look for an acceptable combination of DSKPP
version, variant (in this case, two-pass), key package format, key version, variant (in this case, two-pass), key package format, key
type, and cryptographic algorithms. If the DSKPP Client's SAL type, and cryptographic algorithms. If the DSKPP Client's SAL
does not match the capabilities of the DSKPP Server, or does not does not match the capabilities of the DSKPP Server, or does not
comply with key provisioning policy, then the DSKPP Server will comply with key provisioning policy, then the DSKPP Server will
set the Status attribute to something other than "Success". set the Status attribute to something other than "Success".
Otherwise, Status will be set to "Success". Otherwise, the Status attribute will be set to "Success".
The DSKPP server will validate the DeviceID and KeyID if included The DSKPP Server will validate the DeviceID and KeyID if included
in <KeyProvClientHello>. The DSKPP server MUST NOT accept the in <KeyProvClientHello>. The DSKPP Server MUST NOT accept the
DeviceID unless the server sent the DeviceID in a preceding DeviceID unless the server sent the DeviceID in a preceding
trigger message. Note that it is also legitimate for a DSKPP trigger message. Note that it is also legitimate for a DSKPP
client to initiate the DSKPP protocol run without having received Client to initiate the DSKPP run without having received a
a <KeyProvTrigger> message from a server, but in this case any <KeyProvTrigger> message from a server, but in this case any
provided DeviceID MUST NOT be accepted by the DSKPP server unless provided DeviceID MUST NOT be accepted by the DSKPP Server unless
the server has access to a unique key for the identified device the server has access to a unique key for the identified device
and that key will be used in the protocol. and that key will be used in the protocol.
The DSKPP server MUST use AD to authenticate the user. If The DSKPP Server MUST use AD to authenticate the user. If
authentication fails, then the DSKPP server MUST set the return authentication fails, then the DSKPP Server MUST set the return
code to a failure status, and MUST, in this case, also delete any code to a failure status, and MUST, in this case, also delete any
nonces, keys, and/or secrets associated with the failed run of the nonces, keys, and/or secrets associated with the failed run of the
protocol. protocol.
If user authentication passes, the DSKPP server generates a key If user authentication passes, the DSKPP Server generates a key
K_PROV. In the two-pass case, wherein the client does not have K_PROV. In the two-pass case, wherein the client does not have
access to R_S, K_PROV is randomly generated solely by the DSKPP access to R_S, K_PROV is randomly generated solely by the DSKPP
server wherein K_PROV MUST consist of two parts of equal length, Server wherein K_PROV MUST consist of two parts of equal length,
i.e., i.e.,
K_PROV = K_MAC || K_TOKEN K_PROV = K_MAC || K_TOKEN
The length of K_TOKEN (and hence also the length of K_MAC) is The length of K_TOKEN (and hence also the length of K_MAC) is
determined by the type of K_TOKEN, which MUST be one of the key determined by the type of K_TOKEN, which MUST be one of the key
types supported by the DSKPP client. In cases where the desired types supported by the DSKPP Client. In cases where the desired
key length for K_TOKEN is different from the length of K_MAC for key length for K_TOKEN is different from the length of K_MAC for
the underlying MAC algorithm, the greater length of the two MUST the underlying MAC algorithm, the greater length of the two MUST
be chosen to generate K_PROV. The actual MAC key is truncated be chosen to generate K_PROV. The actual MAC key is truncated
from the resulting K_MAC when it is used in the MAC algorithm when from the resulting K_MAC when it is used in the MAC algorithm when
K_MAC is longer than necessary in order to match the desired K_MAC is longer than necessary in order to match the desired
K_TOKEN length. If K_TOKEN is longer than needed in order to K_TOKEN length. If K_TOKEN is longer than needed in order to
match the K_MAC length, the provisioning server and the receiving match the K_MAC length, the provisioning server and the receiving
client must determine the actual secret key length from the target client must determine the actual secret key length from the target
key algorithm and store only the truncated portion of the K_TOKEN. key algorithm and store only the truncated portion of the K_TOKEN.
The truncation MUST take the beginning bytes of the desired length The truncation MUST take the beginning bytes of the desired length
from K_TOKEN or K_MAC for the actual key. For example, when a from K_TOKEN or K_MAC for the actual key. For example, when a
provisioning server provisions an event based HOTP secret key with provisioning server provisions an event based HOTP secret key with
length 20 and MAC algorithm DSKPP-PRF-SHA256 (Appendix D), K_PROV length 20 and MAC algorithm DSKPP-PRF-SHA256 (Appendix D), K_PROV
length will be 64. The derived K_TOKEN and K_MAC will each length will be 64. The derived K_TOKEN and K_MAC will each
consist of 32 bytes. The actual HOTP key should be the first 20 consist of 32 bytes. The actual HOTP key should be the first 20
bytes of the K_TOKEN. bytes of the K_TOKEN.
Once K_PROV is computed, the DSKPP server selects one of the key Once K_PROV is computed, the DSKPP Server selects one of the key
protection methods from the DSKPP client's KPML, and uses that protection methods from the DSKPP Client's KPML, and uses that
method and corresponding payload to encrypt K_PROV. The DSKPP method and corresponding payload to encrypt K_PROV. The DSKPP
server generates a key package to transport the key encryption Server generates a key package to transport the key encryption
method information and the encrypted provisioning key (K_PROV). method information and the encrypted provisioning key (K_PROV).
The encrypted data format is subject to the choice supported by The encrypted data format is subject to the choice supported by
the selected key package. The key package MUST specify and use the selected key package. The key package MUST specify and use
the selected key protection method and the key information that the selected key protection method and the key information that
was received in <KeyProvClientHello>.The key package also includes was received in <KeyProvClientHello>. The key package also
key usage attributes such as expiry date and length. The server includes key usage attributes such as expiry date and length. The
stores the key package and K_TOKEN with a user account on the server stores the key package and K_TOKEN with a user account on
cryptographic server. the cryptographic server.
The server generates a MAC for key confirmation, which the client The server generates a MAC for key confirmation, which the client
will use to avoid a false "Commit" message that would cause the will use to avoid a false "Commit" message that would cause the
cryptographic module to end up in state in which the server does cryptographic module to end up in state in which the server does
not recognize the stored key. not recognize the stored key.
In addition, if an existing key is being renewed, the server In addition, if an existing key is being renewed, the server
generates a second MAC that it will return to the client as server generates a second MAC that it will return to the client as server
authentication data, AD, so that the DSKPP client can confirm that Authentication Data (AD) so that the DSKPP Client can confirm that
the replacement key came from a trusted server. the replacement key came from a trusted server.
The method the DSKPP server MUST use to calculate the key The method the DSKPP Server MUST use to calculate the key
confirmation MAC: confirmation MAC:
msg_hash = SHA-256(msg_1, ..., msg_n) msg_hash = SHA-256(msg_1, ..., msg_n)
dsLen = len(msg_hash) dsLen = len(msg_hash)
MAC = DSKPP-PRF (K_MAC, "MAC 1 computation" || msg_hash || MAC = DSKPP-PRF (K_MAC, "MAC 1 computation" || msg_hash ||
ServerID, dsLen) ServerID, dsLen)
where where
MAC The MAC MUST be calculated using the already MAC The MAC MUST be calculated using the already
skipping to change at page 41, line 31 skipping to change at page 42, line 45
MAC = DSKPP-PRF (K_MAC, "MAC 1 computation" || msg_hash || MAC = DSKPP-PRF (K_MAC, "MAC 1 computation" || msg_hash ||
ServerID, dsLen) ServerID, dsLen)
where where
MAC The MAC MUST be calculated using the already MAC The MAC MUST be calculated using the already
established MAC algorithm and MUST be computed on the established MAC algorithm and MUST be computed on the
(ASCII) string "MAC 1 computation", msg_hash, and (ASCII) string "MAC 1 computation", msg_hash, and
ServerID using the existing MAC key K_MAC. ServerID using the existing MAC key K_MAC.
K_MAC The key that is derived from K_PROV which the DSKPP K_MAC The key that is derived from K_PROV, which the DSKPP
server MUST provide to the cryptographic module. Server MUST provide to the cryptographic module.
msg_hash The message hash, defined in Section 3.4.3, of msg_hash The message hash, defined in Section 3.4.3, of
messages msg_1, ..., msg_n. messages msg_1, ..., msg_n.
ServerID The identifier that the DSKPP server MUST include in ServerID The identifier that the DSKPP Server MUST include in
the <KeyPackage> element of <KeyProvServerFinished>. the <KeyPackage> element of <KeyProvServerFinished>.
If DSKPP-PRF (defined in Section 3.4.2) is used as the MAC If DSKPP-PRF (defined in Section 3.4.2) is used as the MAC
algorithm, then the input parameter s MUST consist of the algorithm, then the input parameter s MUST consist of the
concatenation of the (ASCII) string "MAC 1 computation", msg_hash, concatenation of the (ASCII) string "MAC 1 computation", msg_hash,
and ServerID, and the parameter dsLen MUST be set to the length of and ServerID, and the parameter dsLen MUST be set to the length of
msg_hash. msg_hash.
The method the DSKPP server MUST use to calculate the server The method the DSKPP Server MUST use to calculate the server
authentication MAC: authentication MAC:
The MAC MUST be computed on the (ASCII) string "MAC 2 The MAC MUST be computed on the (ASCII) string "MAC 2
computation", the server identifier ServerID, and R, using a pre- computation", the server identifier ServerID, and R, using a pre-
existing MAC key K_MAC' (the MAC key that existed before this existing MAC key K_MAC' (the MAC key that existed before this
protocol run). Note that the implementation may specify K_MAC' to protocol run). Note that the implementation may specify K_MAC' to
be the value of the K_TOKEN that is being replaced. be the value of the K_TOKEN that is being replaced.
If DSKPP-PRF is used as the MAC algorithm, then the input If DSKPP-PRF is used as the MAC algorithm, then the input
parameter s MUST consist of the concatenation of the (ASCII) parameter s MUST consist of the concatenation of the (ASCII)
string "MAC 2 computation" ServerID, and R. The parameter dsLen string "MAC 2 computation" ServerID, and R. The parameter dsLen
MUST be set to at least 16 (i.e. the length of the MAC MUST be at MUST be set to at least 16 (i.e., the length of the MAC MUST be at
least 16 octets): least 16 octets):
dsLen >= 16 dsLen >= 16
MAC = DSKPP-PRF (K_MAC', "MAC 2 computation" || ServerID || R, MAC = DSKPP-PRF (K_MAC', "MAC 2 computation" || ServerID || R,
dsLen) dsLen)
The MAC algorithm MUST be the same as the algorithm used by the The MAC algorithm MUST be the same as the algorithm used by the
DSKPP server to calculate the key confirmation MAC. DSKPP Server to calculate the key confirmation MAC.
5.2.3. KeyProvServerFinished 5.2.3. KeyProvServerFinished
DSKPP Client DSKPP Server DSKPP Client DSKPP Server
------------ ------------ ------------ ------------
<--- KP, MAC, AD <--- KP, MAC, AD
When this message is sent: When this message is sent:
The DSKPP server will send this message after authenticating the The DSKPP Server will send this message after authenticating the
user and, if authentication passed, generating K_TOKEN and a key user and, if authentication passed, generating K_TOKEN and a key
package, and associating them with the user's account on the package, and associating them with the user's account on the
cryptographic server. cryptographic server.
Purpose of this message: Purpose of this message:
With this message the DSKPP server transports a key package With this message, the DSKPP Server transports a key package
containing the encrypted provisioning key (K_PROV) and key usage containing the encrypted provisioning key (K_PROV) and key usage
attributes. attributes.
What is contained in this message: What is contained in this message:
A status attribute equivalent to the server's return code to A Status attribute equivalent to the server's return code to
<KeyProvClientHello>. If the server found an acceptable set of <KeyProvClientHello>. If the server found an acceptable set of
attributes from the client's SAL, then it sets status to Success. attributes from the client's SAL, then it sets Status to
"Success".
The confirmation message MUST include the Key Package (KP) that The confirmation message MUST include the Key Package (KP) that
holds the DSKPP Server's ID, key ID, key type, encrypted holds the DSKPP Server's ID, key ID, key type, encrypted
provisioning key (K_PROV), encryption method, and additional provisioning key (K_PROV), encryption method, and additional
configuration information. The default symmetric key package configuration information. The default symmetric key package
format MUST be based on the Portable Symmetric Key Container format MUST be based on the Portable Symmetric Key Container
(PSKC) defined in [PSKC]. Alternative formats MAY include (PSKC) defined in [RFC6030]. Alternative formats MAY include
[SKPC-ASN.1], PKCS#12 [PKCS-12], or PKCS#5 XML [PKCS-5-XML]. [RFC6031], PKCS #12 [PKCS-12], or PKCS #5 XML [PKCS-5-XML].
This message MUST include a MAC that the DSKPP client will use for This message MUST include a MAC that the DSKPP Client will use for
key confirmation. This key confirmation MAC is calculated using key confirmation. This key confirmation MAC is calculated using
the "MAC 1 computation" as described in the previous section. the "MAC 1 computation" as described in the previous section.
Finally, if an existing key is being replaced, then this message Finally, if an existing key is being replaced, then this message
MUST also include a server authentication MAC (calculated using MUST also include a server authentication MAC (calculated using
the "MAC 2 computation" as described in the previous section), the "MAC 2 computation" as described in the previous section),
which is passed as AD to the DSKPP client. which is passed as AD to the DSKPP Client.
How the DSKPP client uses this message: How the DSKPP Client uses this message:
After receiving a <KeyProvServerFinished> message with Status = After receiving a <KeyProvServerFinished> message with Status =
"Success", the DSKPP client MUST verify both MACs (MAC and AD). "Success", the DSKPP Client MUST verify both MACs (MAC and AD).
The DSKPP client MUST terminate the DSKPP protocol run if either The DSKPP Client MUST terminate the DSKPP run if either MAC does
MAC does not verify, and MUST, in this case, also delete any not verify, and MUST, in this case, also delete any nonces, keys,
nonces, keys, and/or secrets associated with the failed run of the and/or secrets associated with the failed run of the protocol.
protocol.
If <KeyProvServerFinished> has Status = "Success" and the MACs If <KeyProvServerFinished> has Status = "Success" and the MACs
were verified, then the DSKPP client MUST extract K_PROV from the were verified, then the DSKPP Client MUST extract K_PROV from the
provided key package, and derive K_TOKEN. Finally, the DSKPP provided key package, and derive K_TOKEN. Finally, the DSKPP
client initializes the cryptographic module with K_TOKEN and the Client initializes the cryptographic module with K_TOKEN and the
corresponding key usage attributes. After this operation, it MUST corresponding key usage attributes. After this operation, it MUST
NOT be possible to overwrite the key unless knowledge of an NOT be possible to overwrite the key unless knowledge of an
authorizing key is proven through a MAC on a later authorizing key is proven through a MAC on a later
<KeyProvServerFinished> message. <KeyProvServerFinished> message.
6. Protocol Extensions 6. Protocol Extensions
DSKPP has been designed to be extensible. The sub-sections below DSKPP has been designed to be extensible. The sub-sections below
define two extensions that are included with the DSKPP schema. Since define two extensions that are included with the DSKPP schema. Since
it is possible that the use of extensions will harm interoperability, it is possible that the use of extensions will harm interoperability,
protocol designers are advised to carefully consider the use of protocol designers are advised to carefully consider the use of
extensions. For example, if a particular implementation relies on extensions. For example, if a particular implementation relies on
the presence of a proprietary extension, then it may not be able to the presence of a proprietary extension, then it may not be able to
interoperate with independent implementations that have no knowledge interoperate with independent implementations that have no knowledge
of this extension. of this extension.
Extensions may be sent with any DSKPP message using the Extensions may be sent with any DSKPP message using the
ExtensionsType. The ExtensionsType type is a list of Extensions ExtensionsType. The ExtensionsType type is a list of Extensions
containing type-value pairs that define optional features supported containing type-value pairs that define optional features supported
by a DSKPP client or server. Each extension MAY be marked as by a DSKPP Client or server. Each extension MAY be marked as
Critical by setting the "Critical" attribute of the Extension to Critical by setting the Critical attribute of the Extension to
"true". Unless an extension is marked as Critical, a receiving party "true". Unless an extension is marked as Critical, a receiving party
need not be able to interpret it; a receiving party is always free to need not be able to interpret it; a receiving party is always free to
disregard any (non-critical) extensions. disregard any (non-critical) extensions.
6.1. The ClientInfoType Extension 6.1. The ClientInfoType Extension
The ClientInfoType extension MAY contain any client-specific data The ClientInfoType extension MAY contain any client-specific data
required of an application. This extension MAY be present in a required of an application. This extension MAY be present in a
<KeyProvClientHello> or <KeyProvClientNonce> message. When present, <KeyProvClientHello> or <KeyProvClientNonce> message. When present,
this extension MUST NOT be marked as Critical. this extension MUST NOT be marked as Critical.
DSKPP servers MUST support this extension. DSKPP servers MUST NOT DSKPP Servers MUST support this extension. DSKPP Servers MUST NOT
attempt to interpret the data it carries and, if received, MUST attempt to interpret the data it carries and, if received, MUST
include it unmodified in the current protocol run's next server include it unmodified in the current protocol run's next server
response. DSKPP servers need not retain the ClientInfoType data. response. DSKPP Servers need not retain the ClientInfoType data.
6.2. The ServerInfoType Extension 6.2. The ServerInfoType Extension
The ServerInfoType extension MAY contain any server-specific data The ServerInfoType extension MAY contain any server-specific data
required of an application, e.g., state information. This extension required of an application, e.g., state information. This extension
is only valid in <KeyProvServerHello> messages for which the Status is only valid in <KeyProvServerHello> messages for which the Status
attribute is set to "Continue". When present, this extension MUST attribute is set to "Continue". When present, this extension MUST
NOT be marked as Critical. NOT be marked as Critical.
DSKPP clients MUST support this extension. DSKPP clients MUST NOT DSKPP Clients MUST support this extension. DSKPP Clients MUST NOT
attempt to interpret the data it carries and, if received, MUST attempt to interpret the data it carries and, if received, MUST
include it unmodified in the current protocol run's next client include it unmodified in the current protocol run's next client
request (i.e., the <KeyProvClientNonce> message). DSKPP clients need request (i.e., the <KeyProvClientNonce> message). DSKPP Clients need
not retain the ServerInfoType data. not retain the ServerInfoType data.
7. Protocol Bindings 7. Protocol Bindings
7.1. General Requirements 7.1. General Requirements
DSKPP assumes a reliable transport. DSKPP assumes a reliable transport.
7.2. HTTP/1.1 Binding for DSKPP 7.2. HTTP/1.1 Binding for DSKPP
This section presents a binding of the previous messages to HTTP/1.1 This section presents a binding of the previous messages to HTTP/1.1
[RFC2616]. This HTTP binding is mandatory-to-implement, although [RFC2616]. This HTTP binding is mandatory to implement, although
newer versions of the specification might define additional bindings newer versions of the specification might define additional bindings
in the future. Note that the HTTP client will normally be different in the future. Note that the HTTP client will normally be different
from the DSKPP client (i.e., the HTTP client will "proxy" DSKPP from the DSKPP Client (i.e., the HTTP client will "proxy" DSKPP
messages from the DSKPP client to the DSKPP server). Likewise, on messages from the DSKPP Client to the DSKPP Server). Likewise, on
the HTTP server side, the DSKPP server MAY receive DSKPP message from the HTTP server side, the DSKPP Server MAY receive DSKPP message from
a "front-end" HTTP server. The DSKPP server will be identified by a a "front-end" HTTP server. The DSKPP Server will be identified by a
specific URL, which may be pre-configured, or provided to the client specific URL, which may be pre-configured, or provided to the client
during initialization. during initialization.
7.2.1. Identification of DSKPP Messages 7.2.1. Identification of DSKPP Messages
The MIME-type for all DSKPP messages MUST be The MIME type for all DSKPP messages MUST be
application/dskpp+xml application/dskpp+xml
7.2.2. HTTP Headers 7.2.2. HTTP Headers
In order to avoid caching of responses carrying DSKPP messages by In order to avoid caching of responses carrying DSKPP messages by
proxies, the following holds: proxies, the following holds:
o When using HTTP/1.1, requesters SHOULD: o When using HTTP/1.1, requesters SHOULD:
* Include a Cache-Control header field set to "no-cache, no- * Include a Cache-Control header field set to "no-cache, no-
skipping to change at page 45, line 44 skipping to change at page 47, line 11
There are no other restrictions on HTTP headers, besides the There are no other restrictions on HTTP headers, besides the
requirement to set the Content-Type header value to the MIME type requirement to set the Content-Type header value to the MIME type
specified in Section 7.2.1. specified in Section 7.2.1.
7.2.3. HTTP Operations 7.2.3. HTTP Operations
Persistent connections as defined in HTTP/1.1 are OPTIONAL. DSKPP Persistent connections as defined in HTTP/1.1 are OPTIONAL. DSKPP
requests are mapped to HTTP requests with the POST method. DSKPP requests are mapped to HTTP requests with the POST method. DSKPP
responses are mapped to HTTP responses. responses are mapped to HTTP responses.
For the 4-pass DSKPP, messages within the protocol run are bound For the four-pass DSKPP, messages within the protocol run are bound
together. In particular, <KeyProvServerHello> is bound to the together. In particular, <KeyProvServerHello> is bound to the
preceding <KeyProvClientHello> by being transmitted in the preceding <KeyProvClientHello> by being transmitted in the
corresponding HTTP response. <KeyProvServerHello> MUST have a corresponding HTTP response. <KeyProvServerHello> MUST have a
SessionID attribute, and the SessionID attribute of the subsequent SessionID attribute, and the SessionID attribute of the subsequent
<KeyProvClientNonce> message MUST be identical. <KeyProvClientNonce> message MUST be identical.
<KeyProvServerFinished> is then once again bound to the rest through <KeyProvServerFinished> is then once again bound to the rest through
HTTP (and possibly through a SessionID). HTTP (and possibly through a SessionID).
7.2.4. HTTP Status Codes 7.2.4. HTTP Status Codes
A DSKPP HTTP responder that refuses to perform a message exchange A DSKPP HTTP responder that refuses to perform a message exchange
with a DSKPP HTTP requester SHOULD return a 403 (Forbidden) response. with a DSKPP HTTP requester SHOULD return a 403 (Forbidden) response.
In this case, the content of the HTTP body is not significant. In In this case, the content of the HTTP body is not significant. In
the case of an HTTP error while processing a DSKPP request, the HTTP the case of an HTTP error while processing a DSKPP request, the HTTP
server MUST return a 500 (Internal Server Error) response. This type server MUST return a 500 (Internal Server Error) response. This type
of error SHOULD be returned for HTTP-related errors detected before of error SHOULD be returned for HTTP-related errors detected before
control is passed to the DSKPP processor, or when the DSKPP processor control is passed to the DSKPP processor, or when the DSKPP processor
reports an internal error (for example, the DSKPP XML namespace is reports an internal error (for example, the DSKPP XML namespace is
incorrect, or the DSKPP schema cannot be located). If a request is incorrect, or the DSKPP schema cannot be located). If a request is
received that is not a DSKPP client message, the DSKPP responder MUST received that is not a DSKPP Client message, the DSKPP responder MUST
return a 400 (Bad request) response. return a 400 (Bad request) response.
In these cases (i.e., when the HTTP response code is 4xx or 5xx), the In these cases (i.e., when the HTTP response code is 4xx or 5xx), the
content of the HTTP body is not significant. content of the HTTP body is not significant.
Redirection status codes (3xx) apply as usual. Redirection status codes (3xx) apply as usual.
Whenever the HTTP POST is successfully invoked, the DSKPP HTTP Whenever the HTTP POST is successfully invoked, the DSKPP HTTP
responder MUST use the 200 status code and provide a suitable DSKPP responder MUST use the 200 status code and provide a suitable DSKPP
message (possibly with DSKPP error information included) in the HTTP message (possibly with DSKPP error information included) in the HTTP
body. body.
7.2.5. HTTP Authentication 7.2.5. HTTP Authentication
No support for HTTP/1.1 authentication is assumed. No support for HTTP/1.1 authentication is assumed.
7.2.6. Initialization of DSKPP 7.2.6. Initialization of DSKPP
If a user requests key initialization in a browsing session, and if If a user requests key initialization in a browsing session, and if
that request has an appropriate Accept header (e.g., to a specific that request has an appropriate Accept header (e.g., to a specific
DSKPP server URL), the DSKPP server MAY respond by sending a DSKPP DSKPP Server URL), the DSKPP Server MAY respond by sending a DSKPP
initialization message in an HTTP response with Content-Type set initialization message in an HTTP response with Content-Type set
according to Section 7.2.1 and response code set to 200 (OK). The according to Section 7.2.1 and response code set to 200 (OK). The
initialization message MAY carry data in its body, such as the URL initialization message MAY carry data in its body, such as the URL
for the DSKPP client to use when contacting the DSKPP server. If the for the DSKPP Client to use when contacting the DSKPP Server. If the
message does carry data, the data MUST be a valid instance of a message does carry data, the data MUST be a valid instance of a
<KeyProvTrigger> element. <KeyProvTrigger> element.
Note that if the user's request was directed to some other resource, Note that if the user's request was directed to some other resource,
the DSKPP server MUST NOT respond by combining the DSKPP content type the DSKPP Server MUST NOT respond by combining the DSKPP content type
with response code 200. In that case, the DSKPP server SHOULD with response code 200. In that case, the DSKPP Server SHOULD
respond by sending a DSKPP initialization message in an HTTP response respond by sending a DSKPP initialization message in an HTTP response
with Content-Type set according to Section 7.2.1 and response code with Content-Type set according to Section 7.2.1 and response code
set to 406 (Not Acceptable). set to 406 (Not Acceptable).
7.2.7. Example Messages 7.2.7. Example Messages
a. Initialization from DSKPP server: a. Initialization from DSKPP Server:
HTTP/1.1 200 OK HTTP/1.1 200 OK
Cache-Control: no-store Cache-Control: no-store
Content-Type: application/dskpp+xml Content-Type: application/dskpp+xml
Content-Length: <some value> Content-Length: <some value>
DSKPP initialization data in XML form... DSKPP initialization data in XML form...
b. Initial request from DSKPP client: b. Initial request from DSKPP Client:
POST http://example.com/cgi-bin/DSKPP-server HTTP/1.1 POST http://example.com/cgi-bin/DSKPP-server HTTP/1.1
Cache-Control: no-cache, no-store Cache-Control: no-cache, no-store
Pragma: no-cache Pragma: no-cache
Host: www.example.com Host: www.example.com
Content-Type: application/dskpp+xml Content-Type: application/dskpp+xml
Content-Length: <some value> Content-Length: <some value>
DSKPP data in XML form (supported version, supported DSKPP data in XML form (supported version, supported
algorithms...) algorithms...)
c. Initial response from DSKPP server: c. Initial response from DSKPP Server:
HTTP/1.1 200 OK HTTP/1.1 200 OK
Cache-Control: no-cache, no-must-revalidate, private Cache-Control: no-cache, no-must-revalidate, private
Pragma: no-cache Pragma: no-cache
Content-Type: application/dskpp+xml Content-Type: application/dskpp+xml
Content-Length: <some value> Content-Length: <some value>
DSKPP data in XML form (server random nonce, server public key, DSKPP data in XML form (server random nonce, server public key,
...) ...)
8. DSKPP XML Schema 8. DSKPP XML Schema
8.1. General Processing Requirements 8.1. General Processing Requirements
Some DSKPP elements rely on the parties being able to compare Some DSKPP elements rely on the parties being able to compare
received values with stored values. Unless otherwise noted, all received values with stored values. Unless otherwise noted, all
elements that have the XML Schema "xs:string" type, or a type derived elements that have the XML schema "xs:string" type, or a type derived
from it, MUST be compared using an exact binary comparison. In from it, MUST be compared using an exact binary comparison. In
particular, DSKPP implementations MUST NOT depend on case-insensitive particular, DSKPP implementations MUST NOT depend on case-insensitive
string comparisons, normalization or trimming of white space, or string comparisons, normalization or trimming of white space, or
conversion of locale-specific formats such as numbers. conversion of locale-specific formats such as numbers.
Implementations that compare values that are represented using Implementations that compare values that are represented using
different character encodings MUST use a comparison method that different character encodings MUST use a comparison method that
returns the same result as converting both values to the Unicode returns the same result as converting both values to the Unicode
character encoding [UNICODE] and then performing an exact binary character encoding [UNICODE] and then performing an exact binary
comparison. comparison.
skipping to change at page 51, line 21 skipping to change at page 52, line 39
</xs:sequence> </xs:sequence>
</xs:complexType> </xs:complexType>
<xs:simpleType name="KeyPackageFormatType"> <xs:simpleType name="KeyPackageFormatType">
<xs:restriction base="xs:anyURI" /> <xs:restriction base="xs:anyURI" />
</xs:simpleType> </xs:simpleType>
<xs:complexType name="AuthenticationDataType"> <xs:complexType name="AuthenticationDataType">
<xs:annotation> <xs:annotation>
<xs:documentation xml:lang="en"> <xs:documentation xml:lang="en">
Authentication data contains a MAC. Authentication Data contains a MAC.
</xs:documentation> </xs:documentation>
</xs:annotation> </xs:annotation>
<xs:sequence> <xs:sequence>
<xs:element name="ClientID" <xs:element name="ClientID"
type="dskpp:IdentifierType" minOccurs="0"/> type="dskpp:IdentifierType" minOccurs="0"/>
<xs:choice> <xs:choice>
<xs:element name="AuthenticationCodeMac" <xs:element name="AuthenticationCodeMac"
type="dskpp:AuthenticationMacType"/> type="dskpp:AuthenticationMacType"/>
<xs:any namespace="##other" processContents="strict" /> <xs:any namespace="##other" processContents="strict" />
</xs:choice> </xs:choice>
skipping to change at page 53, line 31 skipping to change at page 55, line 8
<xs:element name="KeyProvTrigger" <xs:element name="KeyProvTrigger"
type="dskpp:KeyProvTriggerType"> type="dskpp:KeyProvTriggerType">
<xs:annotation> <xs:annotation>
<xs:documentation> DSKPP PDUs </xs:documentation> <xs:documentation> DSKPP PDUs </xs:documentation>
</xs:annotation> </xs:annotation>
</xs:element> </xs:element>
<xs:complexType name="KeyProvTriggerType"> <xs:complexType name="KeyProvTriggerType">
<xs:annotation> <xs:annotation>
<xs:documentation xml:lang="en"> <xs:documentation xml:lang="en">
Message used to trigger the device to initiate a Message used to trigger the device to initiate a
DSKPP protocol run. DSKPP run.
</xs:documentation> </xs:documentation>
</xs:annotation> </xs:annotation>
<xs:sequence> <xs:sequence>
<xs:choice> <xs:choice>
<xs:element name="InitializationTrigger" <xs:element name="InitializationTrigger"
type="dskpp:InitializationTriggerType" /> type="dskpp:InitializationTriggerType" />
<xs:any namespace="##other" processContents="strict"/> <xs:any namespace="##other" processContents="strict"/>
</xs:choice> </xs:choice>
</xs:sequence> </xs:sequence>
<xs:attribute name="Version" type="dskpp:VersionType"/> <xs:attribute name="Version" type="dskpp:VersionType"/>
skipping to change at page 54, line 5 skipping to change at page 55, line 30
<xs:element name="KeyProvClientHello" <xs:element name="KeyProvClientHello"
type="dskpp:KeyProvClientHelloPDU"> type="dskpp:KeyProvClientHelloPDU">
<xs:annotation> <xs:annotation>
<xs:documentation>KeyProvClientHello PDU</xs:documentation> <xs:documentation>KeyProvClientHello PDU</xs:documentation>
</xs:annotation> </xs:annotation>
</xs:element> </xs:element>
<xs:complexType name="KeyProvClientHelloPDU"> <xs:complexType name="KeyProvClientHelloPDU">
<xs:annotation> <xs:annotation>
<xs:documentation xml:lang="en"> <xs:documentation xml:lang="en">
Message sent from DSKPP client to DSKPP server to Message sent from DSKPP Client to DSKPP Server to
initiate a DSKPP session. initiate a DSKPP session.
</xs:documentation> </xs:documentation>
</xs:annotation> </xs:annotation>
<xs:complexContent mixed="false"> <xs:complexContent mixed="false">
<xs:extension base="dskpp:AbstractRequestType"> <xs:extension base="dskpp:AbstractRequestType">
<xs:sequence> <xs:sequence>
<xs:element minOccurs="0" name="DeviceIdentifierData" <xs:element minOccurs="0" name="DeviceIdentifierData"
type="dskpp:DeviceIdentifierDataType" /> type="dskpp:DeviceIdentifierDataType" />
<xs:element minOccurs="0" name="KeyID" <xs:element minOccurs="0" name="KeyID"
type="xs:base64Binary" /> type="xs:base64Binary" />
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<xs:element name="KeyProvServerHello" <xs:element name="KeyProvServerHello"
type="dskpp:KeyProvServerHelloPDU"> type="dskpp:KeyProvServerHelloPDU">
<xs:annotation> <xs:annotation>
<xs:documentation>KeyProvServerHello PDU</xs:documentation> <xs:documentation>KeyProvServerHello PDU</xs:documentation>
</xs:annotation> </xs:annotation>
</xs:element> </xs:element>
<xs:complexType name="KeyProvServerHelloPDU"> <xs:complexType name="KeyProvServerHelloPDU">
<xs:annotation> <xs:annotation>
<xs:documentation xml:lang="en"> <xs:documentation xml:lang="en">
Response message sent from DSKPP server to DSKPP client Response message sent from DSKPP Server to DSKPP Client
in four-pass DSKPP. in four-pass DSKPP.
</xs:documentation> </xs:documentation>
</xs:annotation> </xs:annotation>
<xs:complexContent mixed="false"> <xs:complexContent mixed="false">
<xs:extension base="dskpp:AbstractResponseType"> <xs:extension base="dskpp:AbstractResponseType">
<xs:sequence minOccurs="0"> <xs:sequence minOccurs="0">
<xs:element name="KeyType" <xs:element name="KeyType"
type="dskpp:AlgorithmType"/> type="dskpp:AlgorithmType"/>
<xs:element name="EncryptionAlgorithm" <xs:element name="EncryptionAlgorithm"
type="dskpp:AlgorithmType" /> type="dskpp:AlgorithmType" />
skipping to change at page 55, line 25 skipping to change at page 57, line 4
type="dskpp:KeyPackageFormatType" /> type="dskpp:KeyPackageFormatType" />
<xs:element name="Payload" type="dskpp:PayloadType"/> <xs:element name="Payload" type="dskpp:PayloadType"/>
<xs:element minOccurs="0" name="Extensions" <xs:element minOccurs="0" name="Extensions"
type="dskpp:ExtensionsType" /> type="dskpp:ExtensionsType" />
<xs:element minOccurs="0" name="Mac" <xs:element minOccurs="0" name="Mac"
type="dskpp:MacType"/> type="dskpp:MacType"/>
</xs:sequence> </xs:sequence>
</xs:extension> </xs:extension>
</xs:complexContent> </xs:complexContent>
</xs:complexType> </xs:complexType>
<xs:element name="KeyProvClientNonce" <xs:element name="KeyProvClientNonce"
type="dskpp:KeyProvClientNoncePDU"> type="dskpp:KeyProvClientNoncePDU">
<xs:annotation> <xs:annotation>
<xs:documentation>KeyProvClientNonce PDU</xs:documentation> <xs:documentation>KeyProvClientNonce PDU</xs:documentation>
</xs:annotation> </xs:annotation>
</xs:element> </xs:element>
<xs:complexType name="KeyProvClientNoncePDU"> <xs:complexType name="KeyProvClientNoncePDU">
<xs:annotation> <xs:annotation>
<xs:documentation xml:lang="en"> <xs:documentation xml:lang="en">
Response message sent from DSKPP client to Response message sent from DSKPP Client to
DSKPP server in a four-pass DSKPP session. DSKPP Server in a four-pass DSKPP session.
</xs:documentation> </xs:documentation>
</xs:annotation> </xs:annotation>
<xs:complexContent mixed="false"> <xs:complexContent mixed="false">
<xs:extension base="dskpp:AbstractRequestType"> <xs:extension base="dskpp:AbstractRequestType">
<xs:sequence> <xs:sequence>
<xs:element name="EncryptedNonce" <xs:element name="EncryptedNonce"
type="xs:base64Binary"/> type="xs:base64Binary"/>
<xs:element minOccurs="0" name="AuthenticationData" <xs:element minOccurs="0" name="AuthenticationData"
type="dskpp:AuthenticationDataType" /> type="dskpp:AuthenticationDataType" />
<xs:element minOccurs="0" name="Extensions" <xs:element minOccurs="0" name="Extensions"
skipping to change at page 56, line 19 skipping to change at page 57, line 44
type="dskpp:KeyProvServerFinishedPDU"> type="dskpp:KeyProvServerFinishedPDU">
<xs:annotation> <xs:annotation>
<xs:documentation> <xs:documentation>
KeyProvServerFinished PDU KeyProvServerFinished PDU
</xs:documentation> </xs:documentation>
</xs:annotation> </xs:annotation>
</xs:element> </xs:element>
<xs:complexType name="KeyProvServerFinishedPDU"> <xs:complexType name="KeyProvServerFinishedPDU">
<xs:annotation> <xs:annotation>
<xs:documentation xml:lang="en"> <xs:documentation xml:lang="en">
Final message sent from DSKPP server to DSKPP client in Final message sent from DSKPP Server to DSKPP Client in
a DSKPP session. A MAC value serves for key a DSKPP session. A MAC value serves for key
confirmation, and optional AuthenticationData serves for confirmation, and optional AuthenticationData serves for
server authentication. server authentication.
</xs:documentation> </xs:documentation>
</xs:annotation> </xs:annotation>
<xs:complexContent mixed="false"> <xs:complexContent mixed="false">
<xs:extension base="dskpp:AbstractResponseType"> <xs:extension base="dskpp:AbstractResponseType">
<xs:sequence minOccurs="0"> <xs:sequence minOccurs="0">
<xs:element name="KeyPackage" <xs:element name="KeyPackage"
type="dskpp:KeyPackageType" /> type="dskpp:KeyPackageType" />
<xs:element minOccurs="0" name="Extensions" <xs:element minOccurs="0" name="Extensions"
skipping to change at page 56, line 44 skipping to change at page 58, line 21
type="dskpp:AuthenticationMacType" /> type="dskpp:AuthenticationMacType" />
</xs:sequence> </xs:sequence>
</xs:extension> </xs:extension>
</xs:complexContent> </xs:complexContent>
</xs:complexType> </xs:complexType>
</xs:schema> </xs:schema>
9. Conformance Requirements 9. Conformance Requirements
In order to assure that all implementations of DSKPP can In order to assure that all implementations of DSKPP can
interoperate, the DSKPP server: interoperate, the DSKPP Server:
a. MUST implement the four-pass variation of the protocol a. MUST implement the four-pass variation of the protocol
(Section 4) (Section 4)
b. MUST implement the two-pass variation of the protocol (Section 5) b. MUST implement the two-pass variation of the protocol (Section 5)
c. MUST support user authentication (Section 3.2.1) c. MUST support user authentication (Section 3.2.1)
d. MUST support the following key derivation functions: d. MUST support the following key derivation functions:
* DSKPP-PRF-AES DSKPP-PRF realization (Appendix D) * DSKPP-PRF-AES DSKPP-PRF realization (Appendix D)
skipping to change at page 57, line 34 skipping to change at page 59, line 9
* AES-CBC-128; refer to [FIPS197-AES] * AES-CBC-128; refer to [FIPS197-AES]
g. MUST support the following encryption algorithms for asymmetric g. MUST support the following encryption algorithms for asymmetric
key operations, e.g., key transport: key operations, e.g., key transport:
* RSA Encryption Scheme [PKCS-1] * RSA Encryption Scheme [PKCS-1]
h. MUST support the following integrity/KDF MAC functions: h. MUST support the following integrity/KDF MAC functions:
* DSKPP-PRF-AES (Appendix D) * DSKPP-PRF-AES (Appendix D)
* DSKPP-PRF-SHA256 (Appendix D) * DSKPP-PRF-SHA256 (Appendix D)
i. MUST support the PSKC key package [PSKC]; all three PSKC key i. MUST support the PSKC key package [RFC6030]; all three PSKC key
protection methods (Key Transport, Key Wrap, and Passphrase-Based protection methods (Key Transport, Key Wrap, and Passphrase-Based
Key Wrap) MUST be implemented Key Wrap) MUST be implemented
j. MAY support the ASN.1 key package as defined in [SKPC-ASN.1] j. MAY support the ASN.1 key package as defined in [RFC6031]
DSKPP clients MUST support either the two-pass or the four-pass DSKPP Clients MUST support either the two-pass or the four-pass
variant of the protocol. DSKPP clients MUST fulfill all requirements variant of the protocol. DSKPP Clients MUST fulfill all requirements
listed in item (c) - (j). listed in item (c) - (j).
Finally, implementations of DSKPP MUST bind DSKPP messages to Finally, implementations of DSKPP MUST bind DSKPP messages to
HTTP/1.1 as described in Section 7.2. HTTP/1.1 as described in Section 7.2.
Of course, DSKPP is a security protocol, and one of its major Of course, DSKPP is a security protocol, and one of its major
functions is to allow only authorized parties to successfully functions is to allow only authorized parties to successfully
initialize a cryptographic module with a new symmetric key. initialize a cryptographic module with a new symmetric key.
Therefore, a particular implementation may be configured with any of Therefore, a particular implementation may be configured with any of
a number of restrictions concerning algorithms and trusted a number of restrictions concerning algorithms and trusted
authorities that will prevent universal interoperability. authorities that will prevent universal interoperability.
10. Security Considerations 10. Security Considerations
10.1. General 10.1. General
DSKPP is designed to protect generated keying material from exposure. DSKPP is designed to protect generated keying material from exposure.
No other entities than the DSKPP server and the cryptographic module No entities other than the DSKPP Server and the cryptographic module
will have access to a generated K_TOKEN if the cryptographic will have access to a generated K_TOKEN if the cryptographic
algorithms used are of sufficient strength and, on the DSKPP client algorithms used are of sufficient strength and, on the DSKPP Client
side, generation and encryption of R_C and generation of K_TOKEN take side, generation and encryption of R_C and generation of K_TOKEN take
place as specified in the cryptographic module. This applies even if place as specified in the cryptographic module. This applies even if
malicious software is present in the DSKPP client. However, as malicious software is present in the DSKPP Client. However, as
discussed in the following sub-sections, DSKPP does not protect discussed in the following sub-sections, DSKPP does not protect
against certain other threats resulting from man-in-the-middle against certain other threats resulting from man-in-the-middle
attacks and other forms of attacks. DSKPP MUST, therefore, be run attacks and other forms of attacks. DSKPP MUST, therefore, be run
over a transport providing confidentiality and integrity, such as over a transport providing confidentiality and integrity, such as
HTTP over Transport Layer Security (TLS) with a suitable ciphersuite HTTP over Transport Layer Security (TLS) with a suitable ciphersuite
[RFC2818], when such threats are a concern. Note that TLS [RFC2818], when such threats are a concern. Note that TLS
ciphersuites with anonymous key exchanges are not suitable in those ciphersuites with anonymous key exchanges are not suitable in those
situations [RFC5246]. situations [RFC5246].
10.2. Active Attacks 10.2. Active Attacks
10.2.1. Introduction 10.2.1. Introduction
An active attacker MAY attempt to modify, delete, insert, replay, or An active attacker MAY attempt to modify, delete, insert, replay, or
reorder messages for a variety of purposes including service denial reorder messages for a variety of purposes including service denial
and compromise of generated keying material. and compromise of generated keying material.
10.2.2. Message Modifications 10.2.2. Message Modifications
Modifications to a <KeyProvTrigger> message will either cause denial- Modifications to a <KeyProvTrigger> message will either cause denial
of-service (modifications of any of the identifiers or the of service (modifications of any of the identifiers or the
authentication code) or will cause the DSKPP client to contact the Authentication Code) or will cause the DSKPP Client to contact the
wrong DSKPP server. The latter is in effect a man-in-the-middle wrong DSKPP Server. The latter is in effect a man-in-the-middle
attack and is discussed further in Section 10.2.7. attack and is discussed further in Section 10.2.7.
An attacker may modify a <KeyProvClientHello> message. This means An attacker may modify a <KeyProvClientHello> message. This means
that the attacker could indicate a different key or device than the that the attacker could indicate a different key or device than the
one intended by the DSKPP client, and could also suggest other one intended by the DSKPP Client, and could also suggest other
cryptographic algorithms than the ones preferred by the DSKPP client, cryptographic algorithms than the ones preferred by the DSKPP Client,
e.g., cryptographically weaker ones. The attacker could also suggest e.g., cryptographically weaker ones. The attacker could also suggest
earlier versions of the DSKPP protocol, in case these versions have earlier versions of DSKPP, in case these versions have been shown to
been shown to have vulnerabilities. These modifications could lead have vulnerabilities. These modifications could lead to an attacker
to an attacker succeeding in initializing or modifying another succeeding in initializing or modifying another cryptographic module
cryptographic module than the one intended (i.e., the server than the one intended (i.e., the server assigning the generated key
assigning the generated key to the wrong module), or gaining access to the wrong module) or gaining access to a generated key through the
to a generated key through the use of weak cryptographic algorithms use of weak cryptographic algorithms or protocol versions. DSKPP
or protocol versions. DSKPP implementations MAY protect against the implementations MAY protect against the latter by having strict
latter by having strict policies about what versions and algorithms policies about what versions and algorithms they support and accept.
they support and accept. The former threat (assignment of a The former threat (assignment of a generated key to the wrong module)
generated key to the wrong module) is not possible when the shared- is not possible when the shared-key variant of DSKPP is employed
key variant of DSKPP is employed (assuming existing shared keys are (assuming existing shared keys are unique per cryptographic module),
unique per cryptographic module), but is possible in the public-key but is possible in the public key variation. Therefore, DSKPP
variation. Therefore, DSKPP servers MUST NOT accept unilaterally Servers MUST NOT accept unilaterally provided device identifiers in
provided device identifiers in the public-key variation. This is the public key variation. This is also indicated in the protocol
also indicated in the protocol description. In the shared-key description. In the shared-key variation, however, an attacker may
variation, however, an attacker may be able to provide the wrong be able to provide the wrong identifier (possibly also leading to the
identifier (possibly also leading to the incorrect user being incorrect user being associated with the generated key) if the
associated with the generated key) if the attacker has real-time attacker has real-time access to the cryptographic module with the
access to the cryptographic module with the identified key. The identified key. The result of this attack could be that the
result of this attack could be that the generated key is associated generated key is associated with the correct cryptographic module but
with the correct cryptographic module but the module is associated the module is associated with the incorrect user. See Section 10.5
with the incorrect user. See further Section 10.5 for a discussion for a further discussion of this threat and possible countermeasures.
of this threat and possible countermeasures.
An attacker may also modify a <KeyProvServerHello> message. This An attacker may also modify a <KeyProvServerHello> message. This
means that the attacker could indicate different key types, means that the attacker could indicate different key types,
algorithms, or protocol versions than the legitimate server would, algorithms, or protocol versions than the legitimate server would,
e.g., cryptographically weaker ones. The attacker may also provide a e.g., cryptographically weaker ones. The attacker may also provide a
different nonce than the one sent by the legitimate server. Clients different nonce than the one sent by the legitimate server. Clients
MAY protect against the former through strict adherence to policies MAY protect against the former through strict adherence to policies
regarding permissible algorithms and protocol versions. The latter regarding permissible algorithms and protocol versions. The latter
(wrong nonce) will not constitute a security problem, as a generated (wrong nonce) will not constitute a security problem, as a generated
key will not match the key generated on the legitimate server. Also, key will not match the key generated on the legitimate server. Also,
skipping to change at page 59, line 48 skipping to change at page 61, line 27
wrapped for the legitimate server. Modifications of the wrapped for the legitimate server. Modifications of the
<EncryptedNonce> element, e.g., replacing it with a value for which <EncryptedNonce> element, e.g., replacing it with a value for which
the attacker knows an underlying R'C, will not result in the client the attacker knows an underlying R'C, will not result in the client
changing its pre-DSKPP state, since the server will be unable to changing its pre-DSKPP state, since the server will be unable to
provide a valid MAC in its final message to the client. The server provide a valid MAC in its final message to the client. The server
MAY, however, end up storing K'TOKEN rather than K_TOKEN. If the MAY, however, end up storing K'TOKEN rather than K_TOKEN. If the
cryptographic module has been associated with a particular user, then cryptographic module has been associated with a particular user, then
this could constitute a security problem. For a further discussion this could constitute a security problem. For a further discussion
about this threat, and a possible countermeasure, see Section 10.5 about this threat, and a possible countermeasure, see Section 10.5
below. Note that use of TLS does not protect against this attack if below. Note that use of TLS does not protect against this attack if
the attacker has access to the DSKPP client (e.g., through malicious the attacker has access to the DSKPP Client (e.g., through malicious
software, "Trojans") [RFC5246]. software, "Trojans") [RFC5246].
Finally, attackers may also modify the <KeyProvServerFinished> Finally, attackers may also modify the <KeyProvServerFinished>
message. Replacing the <Mac> element will only result in denial-of- message. Replacing the <Mac> element will only result in denial of
service. Replacement of any other element may cause the DSKPP client service. Replacement of any other element may cause the DSKPP Client
to associate, e.g., the wrong service with the generated key. DSKPP to associate, e.g., the wrong service with the generated key. DSKPP
SHOULD be run over a transport providing confidentiality and SHOULD be run over a transport providing confidentiality and
integrity when this is a concern. integrity when this is a concern.
10.2.3. Message Deletion 10.2.3. Message Deletion
Message deletion will not cause any other harm than denial-of- Message deletion will not cause any other harm than denial of
service, since a cryptographic module MUST NOT change its state service, since a cryptographic module MUST NOT change its state
(i.e., "commit" to a generated key) until it receives the final (i.e., "commit" to a generated key) until it receives the final
message from the DSKPP server and successfully has processed that message from the DSKPP Server and successfully has processed that
message, including validation of its MAC. A deleted message, including validation of its MAC. A deleted
<KeyProvServerFinished> message will not cause the server to end up <KeyProvServerFinished> message will not cause the server to end up
in an inconsistent state vis-a-vis the cryptographic module if the in an inconsistent state vis-a-vis the cryptographic module if the
server implements the suggestions in Section 10.5. server implements the suggestions in Section 10.5.
10.2.4. Message Insertion 10.2.4. Message Insertion
An active attacker may initiate a DSKPP run at any time, and suggest An active attacker may initiate a DSKPP run at any time, and suggest
any device identifier. DSKPP server implementations MAY receive some any device identifier. DSKPP Server implementations MAY receive some
protection against inadvertently initializing a key or inadvertently protection against inadvertently initializing a key or inadvertently
replacing an existing key or assigning a key to a cryptographic replacing an existing key or assigning a key to a cryptographic
module by initializing the DSKPP run by use of the <KeyProvTrigger>. module by initializing the DSKPP run by use of the <KeyProvTrigger>.
The <AuthenticationData> element allows the server to associate a The <AuthenticationData> element allows the server to associate a
DSKPP protocol run with, e.g., an earlier user-authenticated session. DSKPP run e.g., with an earlier user-authenticated session. The
The security of this method, therefore, depends on the ability to security of this method, therefore, depends on the ability to protect
protect the <AuthenticationData> element in the DSKPP initialization the <AuthenticationData> element in the DSKPP initialization message.
message. If an eavesdropper is able to capture this message, he may If an eavesdropper is able to capture this message, he may race the
race the legitimate user for a key initialization. DSKPP over a legitimate user for a key initialization. DSKPP over a transport
transport providing confidentiality and integrity, coupled with the providing confidentiality and integrity, coupled with the
recommendations in Section 10.5, is RECOMMENDED when this is a recommendations in Section 10.5, is RECOMMENDED when this is a
concern. concern.
Insertion of other messages into an existing protocol run is seen as Insertion of other messages into an existing protocol run is seen as
equivalent to modification of legitimately sent messages. equivalent to modification of legitimately sent messages.
10.2.5. Message Replay 10.2.5. Message Replay
During 4-pass DSKPP, attempts to replay a previously recorded DSKPP During four-pass DSKPP, attempts to replay a previously recorded
message will be detected, as the use of nonces ensures that both DSKPP message will be detected, as the use of nonces ensures that
parties are live. For example, a DSKPP client knows that a server it both parties are live. For example, a DSKPP Client knows that a
is communicating with is "live" since the server MUST create a MAC on server it is communicating with is "live" since the server MUST
information sent by the client. create a MAC on information sent by the client.
The same is true for 2-pass DSKPP thanks to the requirement that the The same is true for two-pass DSKPP thanks to the requirement that
client sends R in the <KeyProvClientHello> message and that the the client sends R in the <KeyProvClientHello> message and that the
server includes R in the MAC computation. server includes R in the MAC computation.
10.2.6. Message Reordering 10.2.6. Message Reordering
An attacker may attempt to re-order 4-pass DSKPP messages but this An attacker may attempt to re-order four-pass DSKPP messages but this
will be detected, as each message is of a unique type. Note: Message will be detected, as each message is of a unique type. Note: Message
re-ordering attacks cannot occur in 2-pass DSKPP since each party re-ordering attacks cannot occur in two-pass DSKPP since each party
sends at most one message each. sends at most one message each.
10.2.7. Man-in-the-Middle 10.2.7. Man in the Middle
In addition to other active attacks, an attacker posing as a man-in- In addition to other active attacks, an attacker posing as a man in
the-middle may be able to provide his own public key to the DSKPP the middle may be able to provide his own public key to the DSKPP
client. This threat and countermeasures to it are discussed in Client. This threat and countermeasures to it are discussed in
Section 4.1.1. An attacker posing as a man-in-the-middle may also be Section 4.1.1. An attacker posing as a man in the middle may also be
acting as a proxy and, hence, may not interfere with DSKPP runs but acting as a proxy and, hence, may not interfere with DSKPP runs but
still learn valuable information; see Section 10.3. still learn valuable information; see Section 10.3.
10.3. Passive Attacks 10.3. Passive Attacks
Passive attackers may eavesdrop on DSKPP runs to learn information Passive attackers may eavesdrop on DSKPP runs to learn information
that later on may be used to impersonate users, mount active attacks, that later on may be used to impersonate users, mount active attacks,
etc. etc.
If DSKPP is not run over a transport providing confidentiality, a If DSKPP is not run over a transport providing confidentiality, a
passive attacker may learn: passive attacker may learn:
o What cryptographic modules a particular user is in possession of
o What cryptographic modules a particular user possesses
o The identifiers of keys on those cryptographic modules and other o The identifiers of keys on those cryptographic modules and other
attributes pertaining to those keys, e.g., the lifetime of the attributes pertaining to those keys, e.g., the lifetime of the
keys keys
o DSKPP versions and cryptographic algorithms supported by a o DSKPP versions and cryptographic algorithms supported by a
particular DSKPP client or server particular DSKPP Client or server
o Any value present in an <extension> that is part of o Any value present in an <extension> that is part of
<KeyProvClientHello> <KeyProvClientHello>
Whenever the above is a concern, DSKPP MUST be run over a transport Whenever the above is a concern, DSKPP MUST be run over a transport
providing confidentiality. If man-in-the-middle attacks for the providing confidentiality. If man-in-the-middle attacks for the
purposes described above are a concern, the transport MUST also offer purposes described above are a concern, the transport MUST also offer
server-side authentication. server-side authentication.
10.4. Cryptographic Attacks 10.4. Cryptographic Attacks
An attacker with unlimited access to an initialized cryptographic An attacker with unlimited access to an initialized cryptographic
module may use the module as an "oracle" to pre-compute values that module may use the module as an "oracle" to pre-compute values that
later on may be used to impersonate the DSKPP server. Section 4.1.1 later on may be used to impersonate the DSKPP Server. Section 4.1.1
contains a discussion of this threat and steps RECOMMENDED to protect contains a discussion of this threat and steps RECOMMENDED to protect
against it. against it.
Implementers are advised that cryptographic algorithms become weaker Implementers are advised that cryptographic algorithms become weaker
with time. As new cryptographic techniques are developed and with time. As new cryptographic techniques are developed and
computing performance improves, the work factor to break a particular computing performance improves, the work factor to break a particular
cryptographic algorithm will reduce. Therefore, cryptographic cryptographic algorithm will reduce. Therefore, cryptographic
algorithm implementations SHOULD be modular allowing new algorithms algorithm implementations SHOULD be modular allowing new algorithms
to be readily inserted. That is, implementers SHOULD be prepared to to be readily inserted. That is, implementers SHOULD be prepared to
regularly update the algorithms in their implementations. regularly update the algorithms in their implementations.
10.5. Attacks on the Interaction between DSKPP and User Authentication 10.5. Attacks on the Interaction between DSKPP and User Authentication
If keys generated in DSKPP will be associated with a particular user If keys generated in DSKPP will be associated with a particular user
at the DSKPP server (or a server trusted by, and communicating with at the DSKPP Server (or a server trusted by, and communicating with
the DSKPP server), then in order to protect against threats where an the DSKPP Server), then in order to protect against threats where an
attacker replaces a client-provided encrypted R_C with his own R'C attacker replaces a client-provided encrypted R_C with his own R'C
(regardless of whether the public-key variation or the shared-secret (regardless of whether the public key variation or the shared-secret
variation of DSKPP is employed to encrypt the client nonce), the variation of DSKPP is employed to encrypt the client nonce), the
server SHOULD NOT commit to associate a generated K_TOKEN with the server SHOULD NOT commit to associate a generated K_TOKEN with the
given cryptographic module until the user simultaneously has proven given cryptographic module until the user simultaneously has proven
both possession of the device that hosts the cryptographic module both possession of the device that hosts the cryptographic module
containing K_TOKEN and some out-of-band provided authenticating containing K_TOKEN and some out-of-band provided authenticating
information (e.g., an authentication code). For example, if the information (e.g., an Authentication Code). For example, if the
cryptographic module is a one-time password token, the user could be cryptographic module is a one-time password token, the user could be
required to authenticate with both a one-time password generated by required to authenticate with both a one-time password generated by
the cryptographic module and an out-of-band provided authentication the cryptographic module and an out-of-band provided Authentication
code in order to have the server "commit" to the generated OTP value Code in order to have the server "commit" to the generated OTP value
for the given user. Preferably, the user SHOULD perform this for the given user. Preferably, the user SHOULD perform this
operation from another host than the one used to initialize keys on operation from another host than the one used to initialize keys on
the cryptographic module, in order to minimize the risk of malicious the cryptographic module, in order to minimize the risk of malicious
software on the client interfering with the process. software on the client interfering with the process.
Note: This scenario, wherein the attacker replaces a client-provided Note: This scenario, wherein the attacker replaces a client-provided
R_C with his own R'C, does not apply to 2-pass DSKPP as the client R_C with his own R'C, does not apply to two-pass DSKPP as the client
does not provide any entropy to K_TOKEN. The attack as such (and its does not provide any entropy to K_TOKEN. The attack as such (and its
countermeasures) still applies to 2-pass DSKPP, however, as it countermeasures) still applies to two-pass DSKPP, however, as it
essentially is a man-in-the-middle attack. essentially is a man-in-the-middle attack.
Another threat arises when an attacker is able to trick a user to Another threat arises when an attacker is able to trick a user into
authenticate to the attacker rather than to the legitimate service authenticating to the attacker rather than to the legitimate service
before the DSKPP protocol run. If successful, the attacker will then before the DSKPP run. If successful, the attacker will then be able
be able to impersonate the user towards the legitimate service, and to impersonate the user towards the legitimate service, and
subsequently receive a valid DSKPP trigger. If the public-key subsequently receive a valid DSKPP trigger. If the public key
variant of DSKPP is used, this may result in the attacker being able variant of DSKPP is used, this may result in the attacker being able
to (after a successful DSKPP protocol run) impersonate the user. to (after a successful DSKPP run) impersonate the user. Ordinary
Ordinary precautions MUST, therefore, be in place to ensure that precautions MUST, therefore, be in place to ensure that users
users authenticate only to legitimate services. authenticate only to legitimate services.
10.6. Miscellaneous Considerations 10.6. Miscellaneous Considerations
10.6.1. Client Contributions to K_TOKEN Entropy 10.6.1. Client Contributions to K_TOKEN Entropy
In 4-pass DSKPP, both the client and the server provide randomizing In four-pass DSKPP, both the client and the server provide
material to K_TOKEN, in a manner that allows both parties to verify randomizing material to K_TOKEN, in a manner that allows both parties
that they did contribute to the resulting key. In the 2-pass DSKPP to verify that they did contribute to the resulting key. In the two-
version defined herein, only the server contributes to the entropy of pass DSKPP version defined herein, only the server contributes to the
K_TOKEN. This means that a broken or compromised (pseudo-)random entropy of K_TOKEN. This means that a broken or compromised
number generator in the server may cause more damage than it would in (pseudo)random number generator in the server may cause more damage
the 4-pass variant. Server implementations SHOULD therefore take than it would in the four-pass variant. Server implementations
extreme care to ensure that this situation does not occur. SHOULD therefore take extreme care to ensure that this situation does
not occur.
10.6.2. Key Confirmation 10.6.2. Key Confirmation
4-pass DSKPP servers provide key confirmation through the MAC on R_C four-pass DSKPP Servers provide key confirmation through the MAC on
in the <KeyProvServerFinished> message. In the 2-pass DSKPP variant R_C in the <KeyProvServerFinished> message. In the two-pass DSKPP
described herein, key confirmation is provided by the MAC including variant described herein, key confirmation is provided by the MAC
R, using K_MAC. including R, using K_MAC.
10.6.3. Server Authentication 10.6.3. Server Authentication
DSKPP servers MUST authenticate themselves whenever a successful DSKPP Servers MUST authenticate themselves whenever a successful
DSKPP 2-pass protocol run would result in an existing K_TOKEN being DSKPP two-pass protocol run would result in an existing K_TOKEN being
replaced by a K_TOKEN', or else a denial-of-service attack where an replaced by a K_TOKEN', or else a denial-of-service attack where an
unauthorized DSKPP server replaces a K_TOKEN with another key would unauthorized DSKPP Server replaces a K_TOKEN with another key would
be possible. In 2-pass DSKPP, servers authenticate by including the be possible. In two-pass DSKPP, servers authenticate by including
AuthenticationDataType extension containing a MAC as described in the AuthenticationDataType extension containing a MAC as described in
Section 5 for two-pass DSKPP. Section 5 for two-pass DSKPP.
Whenever a successful DSKPP 2-pass protocol run would result in an Whenever a successful DSKPP two-pass protocol run would result in an
existing K_TOKEN being replaced by a K_TOKEN', the DSKPP client and existing K_TOKEN being replaced by a K_TOKEN', the DSKPP Client and
server MUST do the following to prevent a denial-of-service attack Server MUST do the following to prevent a denial-of-service attack
where an unauthorized DSKPP server replaces a K_TOKEN with another where an unauthorized DSKPP Server replaces a K_TOKEN with another
key: key:
o The DSKPP server MUST use the AuthenticationDataType extension to
o The DSKPP Server MUST use the AuthenticationDataType extension to
transmit a second MAC, calculated as described in Section 5.2.2. transmit a second MAC, calculated as described in Section 5.2.2.
o The DSKPP client MUST authenticate the server using the MAC
o The DSKPP Client MUST authenticate the server using the MAC
contained in the AuthenticationDataType extension received from contained in the AuthenticationDataType extension received from
the DSKPP server to which it is connected. the DSKPP Server to which it is connected.
10.6.4. User Authentication 10.6.4. User Authentication
A DSKPP server MUST authenticate a client to ensure that K_TOKEN is A DSKPP Server MUST authenticate a client to ensure that K_TOKEN is
delivered to the intended device. The following measures SHOULD be delivered to the intended device. The following measures SHOULD be
considered: considered:
o When an Authentication Code is used for client authentication, a o When an Authentication Code is used for client authentication, a
password dictionary attack on the authentication data is possible. password dictionary attack on the Authentication Data is possible.
o The length of the Authentication Code when used over a non-secure o The length of the Authentication Code when used over a non-secure
channel SHOULD be longer than what is used over a secure channel. channel SHOULD be longer than what is used over a secure channel.
When a device, e.g., some mobile phones with small screens, cannot When a device, e.g., some mobile phones with small screens, cannot
handle a long Authentication Code in a user-friendly manner, DSKPP handle a long Authentication Code in a user-friendly manner, DSKPP
SHOULD rely on a secure channel for communication. SHOULD rely on a secure channel for communication.
o In the case that a non-secure channel has to be used, the o In the case that a non-secure channel has to be used, the
Authentication Code SHOULD be sent to the server MAC'd as Authentication Code SHOULD be sent to the server MAC'd as
specified in Section 3.4.1. The Authentication Code and nonce specified in Section 3.4.1. The Authentication Code and nonce
value MUST be strong enough to prevent offline brute-force value MUST be strong enough to prevent offline brute-force
recovery of the Authentication Code from the HMAC data. Given recovery of the Authentication Code from the Hashed MAC (HMAC)
that the nonce value is sent in plaintext format over a non-secure data. Given that the nonce value is sent in plaintext format over
transport, the cryptographic strength of the Authentication Data a non-secure transport, the cryptographic strength of the
depends more on the quality of the Authentication Code. Authentication Data depends more on the quality of the
o When the Authentication Code is sent from the DSKPP server to the Authentication Code.
o When the Authentication Code is sent from the DSKPP Server to the
device in a DSKPP initialization trigger message, an eavesdropper device in a DSKPP initialization trigger message, an eavesdropper
may be able to capture this message and race the legitimate user may be able to capture this message and race the legitimate user
for a key initialization. To prevent this, the transport layer for a key initialization. To prevent this, the transport layer
used to send the DSKPP trigger MUST provide confidentiality and used to send the DSKPP trigger MUST provide confidentiality and
integrity, e.g. a secure browser session. integrity, e.g. a secure browser session.
10.6.5. Key Protection in Two-Pass DSKPP 10.6.5. Key Protection in Two-Pass DSKPP
Three key protection methods are defined for the different usages of Three key protection methods are defined for the different usages of
2-pass DSKPP, which MUST be supported by a key package format, such two-pass DSKPP, which MUST be supported by a key package format, such
as [PSKC] and [SKPC-ASN.1]. Therefore, key protection in the two- as [RFC6030] and [RFC6031]. Therefore, key protection in the two-
pass DSKPP is dependent upon the security of the key package format pass DSKPP is dependent upon the security of the key package format
selected for a protocol run. Some considerations for the Passphrase- selected for a protocol run. Some considerations for the Passphrase-
Based Key Wrap method follow. Based Key Wrap method follow.
The passphrase-based key wrap method SHOULD depend upon the PBKDF2 The Passphrase-Based Key Wrap method SHOULD depend upon the PBKDF2
function from [PKCS-5] to generate an encryption key from a function from [PKCS-5] to generate an encryption key from a
passphrase and salt string. It is important to note that passphrase- passphrase and salt string. It is important to note that passphrase-
based encryption is generally limited in the security that it based encryption is generally limited in the security that it
provides despite the use of salt and iteration count in PBKDF2 to provides despite the use of salt and iteration count in PBKDF2 to
increase the complexity of attack. Implementations SHOULD therefore increase the complexity of attack. Implementations SHOULD therefore
take additional measures to strengthen the security of the take additional measures to strengthen the security of the
passphrase-based key wrap method. The following measures SHOULD be Passphrase-Based Key Wrap method. The following measures SHOULD be
considered where applicable: considered where applicable:
o The passphrase is the same as the one-time password component of o The passphrase is the same as the one-time password component of
the authentication code (see Section 3.4.1) for a description of the Authentication Code (see Section 3.4.1) for a description of
the AC format). The passphrase SHOULD be selected well, and usage the AC format). The passphrase SHOULD be selected well, and usage
guidelines such as the ones in [NIST-PWD] SHOULD be taken into guidelines such as the ones in [NIST-PWD] SHOULD be taken into
account. account.
o A different passphrase SHOULD be used for every key initialization o A different passphrase SHOULD be used for every key initialization
wherever possible (the use of a global passphrase for a batch of wherever possible (the use of a global passphrase for a batch of
cryptographic modules SHOULD be avoided, for example). One way to cryptographic modules SHOULD be avoided, for example). One way to
achieve this is to use randomly-generated passphrases. achieve this is to use randomly generated passphrases.
o The passphrase SHOULD be protected well if stored on the server o The passphrase SHOULD be protected well if stored on the server
and/or on the cryptographic module and SHOULD be delivered to the and/or on the cryptographic module and SHOULD be delivered to the
device's user using secure methods. device's user using secure methods.
o User pre-authentication SHOULD be implemented to ensure that o User pre-authentication SHOULD be implemented to ensure that
K_TOKEN is not delivered to a rogue recipient. K_TOKEN is not delivered to a rogue recipient.
o The iteration count in PBKDF2 SHOULD be high to impose more work o The iteration count in PBKDF2 SHOULD be high to impose more work
for an attacker using brute-force methods (see [PKCS-5] for for an attacker using brute-force methods (see [PKCS-5] for
recommendations). However, it MUST be noted that the higher the recommendations). However, it MUST be noted that the higher the
count, the more work is required on the legitimate cryptographic count, the more work is required on the legitimate cryptographic
module to decrypt the newly delivered K_TOKEN. Servers MAY use module to decrypt the newly delivered K_TOKEN. Servers MAY use
relatively low iteration counts to accommodate devices with relatively low iteration counts to accommodate devices with
limited processing power such as some PDA and cell phones when limited processing power such as some PDA and cell phones when
other security measures are implemented and the security of the other security measures are implemented and the security of the
passphrase-based key wrap method is not weakened. Passphrase-Based Key Wrap method is not weakened.
o Transport level security [RFC5246] SHOULD be used where possible
to protect a two-pass protocol run. Transport level security o TLS [RFC5246] SHOULD be used where possible to protect a two-pass
provides a second layer of protection for the newly generated protocol run. Transport level security provides a second layer of
K_TOKEN. protection for the newly generated K_TOKEN.
10.6.6. Algorithm Agility 10.6.6. Algorithm Agility
Many protocols need to be algorithm agile. One reason for this is Many protocols need to be algorithm agile. One reason for this is
that in the past many protocols had fixed sized fields for that in the past many protocols had fixed sized fields for
information such as hash outputs, keys, etc. This is not the case information such as hash outputs, keys, etc. This is not the case
for DSKPP, except for the key size in the computation of DSKPP-PRF. for DSKPP, except for the key size in the computation of DSKPP-PRF.
Another reason was that protocols did not support algorithm Another reason was that protocols did not support algorithm
negotiation. This is also not the case for DSKPP, except for the use negotiation. This is also not the case for DSKPP, except for the use
of SHA-256 in the MAC confirmation message. Updating the key size of SHA-256 in the MAC confirmation message. Updating the key size
for DSKPP-PRF or the MAC confirmation message algorithm will require for DSKPP-PRF or the MAC confirmation message algorithm will require
a new version of the protocol, which is supported with the Version a new version of the protocol, which is supported with the Version
attribute. attribute.
11. Internationalization Considerations 11. Internationalization Considerations
The DSKPP protocol is meant for machine-to-machine communications; as DSKPP is meant for machine-to-machine communications; as such, its
such, its elements are tokens not meant for direct human consumption. elements are tokens not meant for direct human consumption. DSKPP
DSKPP exchanges information using XML. All XML processors are exchanges information using XML. All XML processors are required to
required to understand UTF-8 [RFC3629] encoding, and therefore all understand UTF-8 [RFC3629] encoding, and therefore all DSKPP Clients
DSKPP clients and servers MUST understand UTF-8 encoded XML. and servers MUST understand UTF-8 encoded XML. Additionally, DSKPP
Additionally, DSKPP servers and clients MUST NOT encode XML with Servers and clients MUST NOT encode XML with encodings other than
encodings other than UTF-8. UTF-8.
12. IANA Considerations 12. IANA Considerations
This document requires several IANA registrations, detailed below. This document requires several IANA registrations, detailed below.
12.1. URN Sub-Namespace Registration 12.1. URN Sub-Namespace Registration
This section registers a new XML namespace, This section registers a new XML namespace,
"urn:ietf:params:xml:ns:keyprov:dskpp" per the guidelines in "urn:ietf:params:xml:ns:keyprov:dskpp" per the guidelines in
[RFC3688]: [RFC3688]:
skipping to change at page 66, line 15 skipping to change at page 68, line 29
12.1. URN Sub-Namespace Registration 12.1. URN Sub-Namespace Registration
This section registers a new XML namespace, This section registers a new XML namespace,
"urn:ietf:params:xml:ns:keyprov:dskpp" per the guidelines in "urn:ietf:params:xml:ns:keyprov:dskpp" per the guidelines in
[RFC3688]: [RFC3688]:
URI: urn:ietf:params:xml:ns:keyprov:dskpp URI: urn:ietf:params:xml:ns:keyprov:dskpp
Registrant Contact: Registrant Contact:
IETF, KEYPROV Working Group (keyprov@ietf.org), Andrea Doherty IETF, KEYPROV Working Group (keyprov@ietf.org), Andrea Doherty
(andrea.doherty@rsa.com) (andrea.doherty@rsa.com)
XML: XML:
BEGIN BEGIN
<?xml version="1.0"?> <?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head> <head>
<title>DSKPP Messsages</title> <title>DSKPP Messages</title>
</head> </head>
<body> <body>
<h1>Namespace for DSKPP Messages</h1> <h1>Namespace for DSKPP Messages</h1>
<h2>urn:ietf:params:xml:ns:keyprov:dskpp</h2> <h2>urn:ietf:params:xml:ns:keyprov:dskpp</h2>
[NOTE TO IANA/RFC-EDITOR: Please replace XXXX below <p>See RFC 6063</p>
with the RFC number for this specification.]
<p>See RFCXXXX</p>
</body> </body>
</html> </html>
END END
12.2. XML Schema Registration 12.2. XML Schema Registration
This section registers an XML schema as per the guidelines in This section registers an XML schema as per the guidelines in
[RFC3688]. [RFC3688].
URI: urn:ietf:params:xml:ns:keyprov:dskpp URI: urn:ietf:params:xml:ns:keyprov:dskpp
skipping to change at page 67, line 14 skipping to change at page 69, line 31
To: ietf-types@iana.org To: ietf-types@iana.org
Subject: Registration of MIME media type application/dskpp+xml Subject: Registration of MIME media type application/dskpp+xml
MIME media type name: application MIME media type name: application
MIME subtype name: dskpp+xml MIME subtype name: dskpp+xml
Required parameters: (none) Required parameters: (none)
Optional parameters: charset Optional parameters: charset
Indicates the character encoding of enclosed XML. Indicates the character encoding of enclosed XML.
Encoding considerations: Uses XML, which can employ 8-bit Encoding considerations: Uses XML, which can employ 8-bit
characters, depending on the character encoding used. See characters, depending on the character encoding used. See
[RFC3203], Section 3.2. Implementations need to support UTF-8 [RFC3023], Section 3.2. Implementations need to support UTF-8
[RFC3629]. [RFC3629].
Security considerations: This content type is designed to carry Security considerations: This content type is designed to carry
protocol data related to key management. Security mechanisms are protocol data related to key management. Security mechanisms are
built into the protocol to ensure that various threats are dealt built into the protocol to ensure that various threats are dealt
with. Refer to Section 10 of the Published Specification for more with. Refer to Section 10 of RFC 6063 for more details
details
Interoperability considerations: None Interoperability considerations: None
Published specification: RFC XXXX [NOTE TO IANA/RFC-EDITOR: Please Published specification: RFC 6063.
replace XXXX with the RFC number for this specification.] Applications that use this media type: Protocol for key exchange.
Applications which use this media type: Protocol for key exchange.
Additional information: Additional information:
Magic Number(s): (none) Magic Number(s): (none)
File extension(s): .xmls File extension(s): .xmls
Macintosh File Type Code(s): (none) Macintosh File Type Code(s): (none)
Person & email address to contact for further information: Person & email address to contact for further information:
Andrea Doherty (andrea.doherty@rsa.com) Andrea Doherty (andrea.doherty@rsa.com)
Intended usage: LIMITED USE Intended usage: LIMITED USE
Author/Change controller: The IETF Author/Change controller: The IETF
Other information: This media type is a specialization of Other information: This media type is a specialization of
application/xml [RFC3203], and many of the considerations application/xml [RFC3023], and many of the considerations
described there also apply to application/dskpp+xml. described there also apply to application/dskpp+xml.
12.4. Status Code Registration 12.4. Status Code Registration
This section registers status codes included in each DSKPP response This section registers status codes included in each DSKPP response
message. The status codes are defined in the schema in the message. The status codes are defined in the schema in the
<StatusCode> type definition contained in the XML schema in <StatusCode> type definition contained in the XML schema in
Section 8. The following summarizes the registry: Section 8. The following summarizes the registry:
Related Registry: Related Registry:
KEYPROV DSKPP Registries, Status codes for DSKPP KEYPROV DSKPP Registries, Status codes for DSKPP
Defining RFC: Defining RFC:
RFC XXXX [NOTE TO IANA/RFC-EDITOR: Please replace XXXX with the RFC 6063.
RFC number for this specification.]
Registration/Assignment Procedures: Registration/Assignment Procedures:
Following the policies outlined in [RFC3575], the IANA policy for Following the policies outlined in [RFC3575], the IANA policy for
assigning new values for the status codes for DSKPP MUST be assigning new values for the status codes for DSKPP MUST be
"Specification Required" and their meanings MUST be documented in "Specification Required" and their meanings MUST be documented in
an RFC or in some other permanent and readily available reference, an RFC or in some other permanent and readily available reference,
in sufficient detail that interoperability between independent in sufficient detail that interoperability between independent
implementations is possible. No mechanism to mark entries as implementations is possible. No mechanism to mark entries as
"deprecated" is envisioned. It is possible to update entries from "deprecated" is envisioned. It is possible to update entries from
the registry. the registry.
skipping to change at page 68, line 26 skipping to change at page 70, line 38
IETF, KEYPROV working group (keyprov@ietf.org), IETF, KEYPROV working group (keyprov@ietf.org),
Andrea Doherty (andrea.doherty@rsa.com) Andrea Doherty (andrea.doherty@rsa.com)
12.5. DSKPP Version Registration 12.5. DSKPP Version Registration
This section registers DSKPP version numbers. The registry has the This section registers DSKPP version numbers. The registry has the
following structure: following structure:
+-------------------------------------------+ +-------------------------------------------+
| DSKPP Version | Specification | | DSKPP Version | Specification |
+-------------------------------------------+ +-------------------------------------------+
| 1.0 | [This document] | | 1.0 | This document |
+-------------------------------------------+ +-------------------------------------------+
Standards action is required to define new versions of DSKPP. It is Standards action is required to define new versions of DSKPP. It is
not envisioned to deprecate, delete, or modify existing DSKPP not envisioned to deprecate, delete, or modify existing DSKPP
versions. versions.
12.6. PRF Algorithm ID Sub-Registry 12.6. PRF Algorithm ID Sub-Registry
This specification relies on a cryptographic primitive, called This specification relies on a cryptographic primitive, called
"DSKPP-PRF" that provides a deterministic transformation of a secret "DSKPP-PRF" that provides a deterministic transformation of a secret
key k and a varying length octet string s to a bit string of key k and a varying length octet string s to a bit string of
specified length dsLen. From the point of view of this specified length dsLen. From the point of view of this
specification, DSKPP-PRF is a "black-box" function that, given the specification, DSKPP-PRF is a "black-box" function that, given the
inputs, generates a pseudorandom value that can be realized by any inputs, generates a pseudorandom value that can be realized by any
appropriate and competent cryptographic technique. . Section 3.4.2 appropriate and competent cryptographic technique. Section 3.4.2
provides two realizations of DSKPP-PRF, DSKPP-PRF-AES and DSKPP-PRF- provides two realizations of DSKPP-PRF, DSKPP-PRF-AES, and DSKPP-PRF-
SHA256. SHA256.
This section registers the identifiers associated with these This section registers the identifiers associated with these
realizations. PRF Algorithm ID Sub-registries are to be subject to realizations. PRF Algorithm ID Sub-registries are to be subject to
Specification Required as per RFC 5226 [RFC5226]. Updates MUST be "Specification Required" as per RFC 5226 [RFC5226]. Updates MUST be
documented in an RFC or in some other permanent and readily available documented in an RFC or in some other permanent and readily available
reference, in sufficient detail that interoperability between reference, in sufficient detail that interoperability between
independent implementations is possible. independent implementations is possible.
Expert approval is required to deprecate a sub-registry. Once Expert approval is required to deprecate a sub-registry. Once
deprecated, the PRF Algorithm ID SHOULD NOT be used in any new deprecated, the PRF Algorithm ID SHOULD NOT be used in any new
implementations. implementations.
12.6.1. DSKPP-PRF-AES 12.6.1. DSKPP-PRF-AES
This section registers the following in the IETF XML namespace
registry.
Common Name: Common Name:
DSKPP-PRF-AES DSKPP-PRF-AES
URI: URI:
urn:ietf:params:xml:ns:keyprov:dskpp:prf-aes-128 urn:ietf:params:xml:ns:keyprov:dskpp:prf-aes-128
Identifier Definition: Identifier Definition:
The DSKPP-PRF-AES algorithm realization is defined in The DSKPP-PRF-AES algorithm realization is defined in
Appendix D.2.2 of this document. Appendix D.2.2 of this document.
Registrant Contact: Registrant Contact:
IETF, KEYPROV working group (keyprov@ietf.org), IETF, KEYPROV working group (keyprov@ietf.org),
Andrea Doherty (andrea.doherty@rsa.com) Andrea Doherty (andrea.doherty@rsa.com)
12.6.2. DSKPP-PRF-SHA256 12.6.2. DSKPP-PRF-SHA256
This section registers the following in the IETF XML namespace
registry.
Common Name: Common Name:
DSKPP-PRF-SHA256 DSKPP-PRF-SHA256
URI: URI:
urn:ietf:params:xml:ns:keyprov:dskpp:prf-sha256 urn:ietf:params:xml:ns:keyprov:dskpp:prf-sha256
Identifier Definition: Identifier Definition:
The DSKPP-PRF-SHA256 algorithm realization is defined in The DSKPP-PRF-SHA256 algorithm realization is defined in
Appendix D.3.2 of this document. Appendix D.3.2 of this document.
skipping to change at page 70, line 15 skipping to change at page 72, line 31
Registration Procedure: Registration Procedure:
Following the policies outlined in [RFC3575], the IANA policy for Following the policies outlined in [RFC3575], the IANA policy for
assigning new values for the status codes for DSKPP MUST be assigning new values for the status codes for DSKPP MUST be
"Specification Required" and their meanings MUST be documented in "Specification Required" and their meanings MUST be documented in
an RFC or in some other permanent and readily available reference, an RFC or in some other permanent and readily available reference,
in sufficient detail that interoperability between independent in sufficient detail that interoperability between independent
implementations is possible. implementations is possible.
Deprecated: Deprecated:
TRUE if based on expert approval this entry has been deprecated TRUE if based on expert approval this entry has been deprecated
and SHOULD NOT be used in any new implementations. Otherwise and SHOULD NOT be used in any new implementations. Otherwise,
FALSE. FALSE.
Identifiers: Identifiers:
The initial URIs for the Key Container defined for this version of The initial URIs for the Key Container defined for this version of
the document are listed here: the document are listed here:
Name: PSKC Key Container Name: PSKC Key Container
URI: urn:ietf:params:xml:ns:keyprov:dskpp:pskc-key-container URI: urn:ietf:params:xml:ns:keyprov:dskpp:pskc-key-container
Specification: [PSKC] Specification: [RFC6030]
Deprecated: FALSE Deprecated: FALSE
Name: SKPC Key Container Name: SKPC Key Container
URI: urn:ietf:params:xml:ns:keyprov:dskpp:skpc-key-container URI: urn:ietf:params:xml:ns:keyprov:dskpp:skpc-key-container
Specification: [SKPC-ASN.1] Specification: [RFC6031]
Deprecated: FALSE Deprecated: FALSE
Name: PKCS12 Key Container Name: PKCS12 Key Container
URI: urn:ietf:params:xml:ns:keyprov:dskpp:pkcs12-key-container URI: urn:ietf:params:xml:ns:keyprov:dskpp:pkcs12-key-container
Specification: [PKCS-12] Specification: [PKCS-12]
Deprecated: FALSE Deprecated: FALSE
Name: PKCS5-XML Key Container Name: PKCS5-XML Key Container
URI: urn:ietf:params:xml:ns:keyprov:dskpp:pkcs5-xml-key-container URI: urn:ietf:params:xml:ns:keyprov:dskpp:pkcs5-xml-key-container
Specification: [PKCS-5-XML] Specification: [PKCS-5-XML]
Deprecated: FALSE Deprecated: FALSE
Registrant Contact: Registrant Contact:
IETF, KEYPROV working group (keyprov@ietf.org), IETF, KEYPROV working group (keyprov@ietf.org),
Andrea Doherty (andrea.doherty@rsa.com) Andrea Doherty (andrea.doherty@rsa.com)
13. Intellectual Property Considerations 13. Intellectual Property Considerations
skipping to change at page 70, line 49 skipping to change at page 73, line 16
Specification: [PKCS-5-XML] Specification: [PKCS-5-XML]
Deprecated: FALSE Deprecated: FALSE
Registrant Contact: Registrant Contact:
IETF, KEYPROV working group (keyprov@ietf.org), IETF, KEYPROV working group (keyprov@ietf.org),
Andrea Doherty (andrea.doherty@rsa.com) Andrea Doherty (andrea.doherty@rsa.com)
13. Intellectual Property Considerations 13. Intellectual Property Considerations
RSA and RSA Security are registered trademarks or trademarks of RSA RSA and RSA Security are registered trademarks or trademarks of RSA
Security Inc. in the United States and/or other countries. The names Security, Inc. in the United States and/or other countries. The
of other products and services mentioned may be the trademarks of names of other products and services mentioned may be the trademarks
their respective owners. of their respective owners.
14. Contributors 14. Contributors
This work is based on information contained in [RFC4758], authored by This work is based on information contained in [RFC4758], authored by
Magnus Nystrom, with enhancements borrowed from an individual Magnus Nystrom, with enhancements borrowed from an individual
Internet-Draft co-authored by Mingliang Pei and Salah Machani (e.g., document coauthored by Mingliang Pei and Salah Machani (e.g., user
User Authentication, and support for multiple key package formats). authentication, and support for multiple key package formats).
We would like to thank Philip Hoyer for his work in aligning DSKPP We would like to thank Philip Hoyer for his work in aligning DSKPP
and PSKC schemas. and PSKC schemas.
We would also like to thank Hannes Tschofenig and Phillip Hallam- We would also like to thank Hannes Tschofenig and Phillip Hallam-
Baker for their draft reviews, feedback, and text contributions. Baker for their reviews, feedback, and text contributions.
15. Acknowledgements 15. Acknowledgements
We would like to thank the following for review of previous DSKPP We would like to thank the following for review of previous DSKPP
document versions: document versions:
o Dr. Ulrike Meyer (Review June 2007) o Dr. Ulrike Meyer (Review June 2007)
o Niklas Neumann (Review June 2007) o Niklas Neumann (Review June 2007)
o Shuh Chang (Review June 2007) o Shuh Chang (Review June 2007)
o Hannes Tschofenig (Review June 2007 and again in August 2007) o Hannes Tschofenig (Review June 2007 and again in August 2007)
skipping to change at page 71, line 37 skipping to change at page 74, line 4
o Sean Turner (Reviews August 2007 and again in July 2008) o Sean Turner (Reviews August 2007 and again in July 2008)
o John Linn (Review August 2007) o John Linn (Review August 2007)
o Philip Hoyer (Review September 2007) o Philip Hoyer (Review September 2007)
o Thomas Roessler (Review November 2007) o Thomas Roessler (Review November 2007)
o Lakshminath Dondeti (Comments December 2007) o Lakshminath Dondeti (Comments December 2007)
o Pasi Eronen (Comments December 2007) o Pasi Eronen (Comments December 2007)
o Phillip Hallam-Baker (Review and Edits November 2008 and again in o Phillip Hallam-Baker (Review and Edits November 2008 and again in
January 2009) January 2009)
o Alexey Melnikov (Review May 2010) o Alexey Melnikov (Review May 2010)
o Peter Saint-Andre (Review May 2010) o Peter Saint-Andre (Review May 2010)
We would also like to thank the following for their input to selected We would also like to thank the following for their input to selected
design aspects of the DSKPP protocol: design aspects of DSKPP:
o Anders Rundgren (Key Package Format and Client Authentication o Anders Rundgren (Key Package Format and Client Authentication
Data) Data)
o Thomas Roessler (HTTP Binding) o Thomas Roessler (HTTP Binding)
o Hannes Tschofenig (HTTP Binding) o Hannes Tschofenig (HTTP Binding)
o Phillip Hallam-Baker (Registry for Algorithms) o Phillip Hallam-Baker (Registry for Algorithms)
o N. Asokan (original observation of weakness in Authentication o N. Asokan (original observation of weakness in Authentication
Data) Data)
Finally, we would like to thank Robert Griffin for opening Finally, we would like to thank Robert Griffin for opening
communication channels for us with the IEEE P1619.3 Key Management communication channels for us with the IEEE P1619.3 Key Management
Group, and facilitating our groups in staying informed of potential Group, and facilitating our groups in staying informed of potential
areas (esp. key provisioning and global key identifiers of areas (especially key provisioning and global key identifiers of
collaboration) of collaboration. collaboration) of collaboration.
16. References 16. References
16.1. Normative references 16.1. Normative References
[FIPS180-SHA] [FIPS180-SHA] National Institute of Standards and Technology,
National Institute of Standards and Technology, "Secure "Secure Hash Standard", FIPS 180-2, February 2004,
Hash Standard", FIPS 180-2, February 2004, <http:// <http://csrc.nist.gov/publications/fips/fips180-2/
csrc.nist.gov/publications/fips/fips180-2/ fips180-2withchangenotice.pdf>.
fips180-2withchangenotice.pdf>.
[FIPS197-AES] [FIPS197-AES] National Institute of Standards and Technology,
National Institute of Standards and Technology, "Specification for the Advanced Encryption Standard
"Specification for the Advanced Encryption Standard (AES)", FIPS 197, November 2001, <http://
(AES)", FIPS 197, November 2001, <http://csrc.nist.gov/ csrc.nist.gov/publications/fips/fips197/
publications/fips/fips197/fips-197.pdf>. fips-197.pdf>.
[ISO3309] "ISO Information Processing Systems - Data Communication - [ISO3309] International Organization for Standardization,
High-Level Data Link Control Procedure - Frame Structure", "ISO Information Processing Systems - Data
IS 3309, 3rd Edition, October 1984. Communication - High-Level Data Link Control
Procedure - Frame Structure", ISO 3309,
3rd Edition, October 1984.
[PKCS-1] RSA Laboratories, "RSA Cryptography Standard", PKCS #1 [PKCS-1] RSA Laboratories, "RSA Cryptography Standard",
Version 2.1, June 2002, PKCS #1 Version 2.1, June 2002,
<http://www.rsasecurity.com/rsalabs/pkcs/>. <http://www.rsasecurity.com/rsalabs/pkcs/>.
[PKCS-5] RSA Laboratories, "Password-Based Cryptography Standard", [PKCS-5] RSA Laboratories, "Password-Based Cryptography
PKCS #5 Version 2.0, March 1999, Standard", PKCS #5 Version 2.0, March 1999,
<http://www.rsasecurity.com/rsalabs/pkcs/>. <http://www.rsasecurity.com/rsalabs/pkcs/>.
[PKCS-5-XML] [PKCS-5-XML] RSA Laboratories, "XML Schema for PKCS #5 Version
RSA Laboratories, "XML Schema for PKCS #5 Version 2.0", 2.0", PKCS #5 Version 2.0 Amd.1 (FINAL DRAFT),
PKCS #5 Version 2.0 Amd.1 (FINAL DRAFT), October 2006, October 2006,
<http://www.rsasecurity.com/rsalabs/pkcs/>. <http://www.rsasecurity.com/rsalabs/pkcs/>.
[PSKC] "Portable Symmetric Key Container", 2010, [RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC:
<http://tools.ietf.org/html/draft-ietf-keyprov-pskc-09>. Keyed-Hashing for Message Authentication",
RFC 2104, February 1997.
[RFC2104] Krawzcyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed- [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Hashing for Message Authentication", RFC 2104, Requirement Levels", BCP 14, RFC 2119, March 1997.
February 1997, <http://www.ietf.org/rfc/rfc2104.txt>.
[RFC2119] "Key words for use in RFCs to Indicate Requirement [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Levels", BCP 14, RFC 2119, March 1997, Masinter, L., Leach, P., and T. Berners-Lee,
<http://www.ietf.org/rfc/rfc2119.txt>. "Hypertext Transfer Protocol -- HTTP/1.1",
RFC 2616, June 1999.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., [RFC3394] Schaad, J. and R. Housley, "Advanced Encryption
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext Standard (AES) Key Wrap Algorithm", RFC 3394,
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999, September 2002.
<http://www.ietf.org/rfc/rfc2616.txt>.
[RFC3394] Schaad , J. and R. Housley, "Advanced Encryption Standard [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
(AES) Key Wrap Algorithm", RFC 3394, September 2002, 10646", STD 63, RFC 3629, November 2003.
<http://www.ietf.org/rfc/rfc3394.txt>.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO10646", [RFC4013] Zeilenga, K., "SASLprep: Stringprep Profile for
STD 63, RFC 3629, November 2003, User Names and Passwords", RFC 4013, February 2005.
<http://www.ietf.org/rfc/rfc3629.txt>.
[RFC4013] Zeilenga, K., "SASLprep: Stringprep Profile for User Names [RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen,
and Passwords", RFC 4013, February 2005, "Internet X.509 Public Key Infrastructure
<http://www.ietf.org/rfc/rfc4013.txt>. Certificate Management Protocol (CMP)", RFC 4210,
September 2005.
[RFC4210] Adams, C., Farrell, S., Kause, T., and T. Mononen, [RFC5272] Schaad, J. and M. Myers, "Certificate Management
"Internet X.509 Public Key Infrastructure Certificate over CMS (CMC)", RFC 5272, June 2008.
Management Protocol (CMP)", RFC 4210, September 2005,
<http://www.ietf.org/rfc/rfc4210.txt>.
[RFC5272] Schaad, J. and M. Myers, "Certificate Management over CMS [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
(CMC)", RFC 5272, June 2008, Housley, R., and W. Polk, "Internet X.509 Public
<http://www.ietf.org/rfc/rfc5272.txt>. Key Infrastructure Certificate and Certificate
Revocation List (CRL) Profile", RFC 5280, May 2008.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., [RFC5649] Housley, R. and M. Dworkin, "Advanced Encryption
Housley, R., and W. Polk, "Internet X.509 Public Key Standard (AES) Key Wrap with Padding Algorithm",
Infrastructure Certificate and Certificate Revocation List RFC 5649, September 2009.
(CRL) Profile", RFC 5280, May 2008,
<http://www.ietf.org/rfc/rfc5280.txt>.
[RFC5649] Housley, R. and M. Dworkin , "Advanced Encryption Standard [RFC6030] Hoyer, P., Pei, M., and S. Machani, "Portable
(AES) Key Wrap with Padding Algorithm", RFC 5649, Symmetric Key Container (PSKC)", RFC 6030,
August 2009, <http://www.ietf.org/rfc/rfc5649.txt>. October 2010.
[UNICODE] Davis, M. and M. Duerst, "Unicode Normalization Forms", [UNICODE] Davis, M. and M. Duerst, "Unicode Normalization
March 2001, Forms", March 2001, <http://www.unicode.org/
<http://www.unicode.org/unicode/reports/tr15/ unicode/reports/tr15/tr15-21.html>.
tr15-21.html>.
[XML] W3C, "Extensible Markup Language (XML) 1.0 (Fifth [XML] W3C, "Extensible Markup Language (XML) 1.0 (Fifth
Edition)", W3C Recommendation, November 2008, Edition)", W3C Recommendation, November 2008,
<http://www.w3.org/TR/2006/REC-xml-20060816/>. <http://www.w3.org/TR/2006/REC-xml-20060816/>.
[XMLDSIG] W3C, "XML Signature Syntax and Processing", [XMLDSIG] W3C, "XML Signature Syntax and Processing",
W3C Recommendation, February 2002, W3C Recommendation, February 2002, <http://
<http://www.w3.org/TR/2002/REC-xmldsig-core-20020212/>. www.w3.org/TR/2002/REC-xmldsig-core-20020212/>.
[XMLENC] W3C, "XML Encryption Syntax and Processing", [XMLENC] W3C, "XML Encryption Syntax and Processing",
W3C Recommendation, December 2002, W3C Recommendation, December 2002, <http://
<http://www.w3.org/TR/2002/REC-xmldsig-core-20020212/>. www.w3.org/TR/2002/REC-xmldsig-core-20020212/>.
16.2. Informative references 16.2. Informative References
[CT-KIP-P11] [CT-KIP-P11] RSA Laboratories, "PKCS #11 Mechanisms for the
RSA Laboratories, "PKCS #11 Mechanisms for the Cryptographic Token Key Initialization Protocol",
Cryptographic Token Key Initialization Protocol", PKCS #11 PKCS #11 Version 2.20 Amd.2, December 2005,
Version 2.20 Amd.2, December 2005, <http://www.rsasecurity.com/rsalabs/pkcs/>.
<http://www.rsasecurity.com/rsalabs/pkcs/>.
[FAQ] RSA Laboratories, "Frequently Asked Questions About [FAQ] RSA Laboratories, "Frequently Asked Questions About
Today's Cryptography", Version 4.1, 2000. Today's Cryptography", Version 4.1, 2000.
[NIST-PWD] [NIST-PWD] National Institute of Standards and Technology,
National Institute of Standards and Technology, "Password "Password Usage", FIPS 112, May 1985,
Usage", FIPS 112, May 1985, <http://www.itl.nist.gov/fipspubs/fip112.htm>.
<http://www.itl.nist.gov/fipspubs/fip112.htm>.
[NIST-SP800-38B] [NIST-SP800-38B] International Organization for Standardization,
International Organization for Standardization, "Recommendations for Block Cipher Modes of
"Recommendations for Block Cipher Modes of Operation: The Operation: The CMAC Mode for Authentication",
CMAC Mode for Authentication", NIST SP800-38B, May 2005, < NIST SP800-38B, May 2005, <http://csrc.nist.gov/
http://csrc.nist.gov/publications/nistpubs/800-38B/ publications/nistpubs/800-38B/SP_800-38B.pdf>.
SP_800-38B.pdf>.
[NIST-SP800-57] [NIST-SP800-57] National Institute of Standards and Technology,
National Institute of Standards and Technology, "Recommendation for Key Management - Part I:
"Recommendation for Key Management - Part I: General General (Revised)", NIST 800-57, March 2007, <http:
(Revised)", NIST 800-57, March 2007, <http:// //csrc.nist.gov/publications/nistpubs/800-57/
csrc.nist.gov/publications/nistpubs/800-57/ sp800-57-Part1-revised2_Mar08-2007.pdf>.
sp800-57-Part1-revised2_Mar08-2007.pdf>.
[PKCS-11] RSA Laboratories, "Cryptographic Token Interface [PKCS-11] RSA Laboratories, "Cryptographic Token Interface
Standard", PKCS #11 Version 2.20, June 2004, Standard", PKCS #11 Version 2.20, June 2004,
<http://www.rsasecurity.com/rsalabs/pkcs/>. <http://www.rsasecurity.com/rsalabs/pkcs/>.
[PKCS-12] "Personal Information Exchange Syntax Standard", PKCS #12 [PKCS-12] "Personal Information Exchange Syntax Standard",
Version 1.0, 2005, PKCS #12 Version 1.0, 2005, <ftp://
<ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-12/ ftp.rsasecurity.com/pub/pkcs/pkcs-12/
pkcs-12v1.pdf>. pkcs-12v1.pdf>.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000, [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
<http://www.ietf.org/rfc/rfc2818.txt>.
[RFC3203] Murata, M., St. Laurent, S., and D. Kohn, "XML Media [RFC3023] Murata, M., St. Laurent, S., and D. Kohn, "XML
Types", RFC 3203, January 2001, Media Types", RFC 3023, January 2001.
<http://www.ietf.org/rfc/rfc3203.txt>.
[RFC3575] Aboba, B., "IANA Considerations for RADIUS", RFC 3575, [RFC3575] Aboba, B., "IANA Considerations for RADIUS (Remote
July 2003, <http://www.ietf.org/rfc/rfc3575.txt>. Authentication Dial In User Service)", RFC 3575,
July 2003.
[RFC3688] Mealling, M., "The IETF XML Registry", RFC 3688, BCP 81, [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81,
January 2004, <http://www.ietf.org/rfc/rfc3688.txt>. RFC 3688, January 2004.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter,
Resource Identifier (URI): Generic Syntax", RFC 3986, "Uniform Resource Identifier (URI): Generic
STD 66, January 2005, Syntax", STD 66, RFC 3986, January 2005.
<http://www.ietf.org/rfc/rfc3986.txt>.
[RFC4758] RSA, The Security Division of EMC, "Cryptographic Token [RFC4758] Nystroem, M., "Cryptographic Token Key
Key Initialization Protocol (CT-KIP)", RFC 4758, Initialization Protocol (CT-KIP) Version 1.0
November 2006, <http://www.ietf.org/rfc/rfc4758.txt>. Revision 1", RFC 4758, November 2006.
[RFC5246] Dierks, T. and E. Rescorla , "The Transport Layer Security [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for
(TLS) Protocol, Version 1.2", RFC 5246, August 2008, Writing an IANA Considerations Section in RFCs",
<http://www.ietf.org/rfc/rfc5246.txt>. BCP 26, RFC 5226, May 2008.
[SKPC-ASN.1] [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer
"Symmetric Key Package Content Type", 2007, <http:// Security (TLS) Protocol Version 1.2", RFC 5246,
www.ietf.org/internet-drafts/ August 2008.
draft-ietf-keyprov-symmetrickeyformat-01.txt>.
[XMLNS] W3C, "Namespaces in XML", W3C Recommendation, [RFC6031] Turner, S. and R. , "Cryptographic Message Syntax
January 1999, (CMS) Symmetric Key Package Content Type",
<http://www.w3.org/TR/2009/REC-xml-names-20091208>. RFC 6031, December 2010.
[XMLNS] W3C, "Namespaces in XML", W3C Recommendation,
January 1999,
<http://www.w3.org/TR/2009/REC-xml-names-20091208>.
Appendix A. Usage Scenarios Appendix A. Usage Scenarios
DSKPP is expected to be used to provision symmetric keys to DSKPP is expected to be used to provision symmetric keys to
cryptographic modules in a number of different scenarios, each with cryptographic modules in a number of different scenarios, each with
its own special requirements, as described below. This appendix its own special requirements, as described below. This appendix
forms an informative part of the document. forms an informative part of the document.
A.1. Single Key Request A.1. Single Key Request
skipping to change at page 76, line 15 skipping to change at page 78, line 33
A.2. Multiple Key Requests A.2. Multiple Key Requests
A cryptographic module makes multiple requests for symmetric keys A cryptographic module makes multiple requests for symmetric keys
from the same provisioning server. The symmetric keys need not be of from the same provisioning server. The symmetric keys need not be of
the same type, i.e., the keys may be used with different symmetric the same type, i.e., the keys may be used with different symmetric
key cryptographic algorithms, including one-time password key cryptographic algorithms, including one-time password
authentication algorithms, and the AES encryption algorithm. authentication algorithms, and the AES encryption algorithm.
A.3. User Authentication A.3. User Authentication
In some deployment scenarios, a key issuer may rely on a third party In some deployment scenarios, a key issuer may rely on a third-party
provisioning service. In this case, the issuer directs provisioning provisioning service. In this case, the issuer directs provisioning
requests from the cryptographic module to the provisioning service. requests from the cryptographic module to the provisioning service.
As such, it is the responsibility of the issuer to authenticate the As such, it is the responsibility of the issuer to authenticate the
user through some out-of-band means before granting him rights to user through some out-of-band means before granting him rights to
acquire keys. Once the issuer has granted those rights, the issuer acquire keys. Once the issuer has granted those rights, the issuer
provides an authentication code to the user and makes it available to provides an Authentication Code to the user and makes it available to
the provisioning service, so that the user can prove that he is the provisioning service, so that the user can prove that he is
authorized to acquire keys. authorized to acquire keys.
A.4. Provisioning Time-Out Policy A.4. Provisioning Time-Out Policy
An issuer may provide a time-limited authentication code to a user An issuer may provide a time-limited Authentication Code to a user
during registration, which the user will input into the cryptographic during registration, which the user will input into the cryptographic
module to authenticate themselves with the provisioning server. The module to authenticate themselves with the provisioning server. The
server will allow a key to be provisioned to the cryptographic module server will allow a key to be provisioned to the cryptographic module
hosted by the user's device when user authentication is required only hosted by the user's device when user authentication is required only
if the user inputs a valid authentication code within the fixed time if the user inputs a valid Authentication Code within the fixed time
period established by the issuer. period established by the issuer.
A.5. Key Renewal A.5. Key Renewal
A cryptographic module requests renewal of the symmetric key material A cryptographic module requests renewal of the symmetric key material
attached to a key ID, as opposed to keeping the key value constant attached to a key ID, as opposed to keeping the key value constant
and refreshing the metadata. Such a need may occur in the case when and refreshing the metadata. Such a need may occur in the case when
a user wants to upgrade her device that houses the cryptographic a user wants to upgrade her device that houses the cryptographic
module or when a key has expired. When a user uses the same module or when a key has expired. When a user uses the same
cryptographic module to, for example, perform strong authentication cryptographic module for example, to perform strong authentication at
at multiple Web login sites, keeping the same key ID removes the need multiple Web login sites, keeping the same key ID removes the need
for the user to register a new key ID at each site. for the user to register a new key ID at each site.
A.6. Pre-Loaded Key Replacement A.6. Pre-Loaded Key Replacement
This scenario represents a special case of symmetric key renewal in This scenario represents a special case of symmetric key renewal in
which a local administrator can authenticate the user procedurally which a local administrator can authenticate the user procedurally
before initiating the provisioning process. It also allows for a before initiating the provisioning process. It also allows for a
device issuer to pre-load a key onto a cryptographic module with a device issuer to pre-load a key onto a cryptographic module with a
restriction that the key is replaced with a new key prior to use of restriction that the key is replaced with a new key prior to use of
the cryptographic module. Another variation of this scenario is the the cryptographic module. Another variation of this scenario is the
skipping to change at page 77, line 32 skipping to change at page 80, line 7
issuance in-the-field provisioning. This secure flow can pass issuance in-the-field provisioning. This secure flow can pass
Transport Layer Security (TLS) [RFC5246] and other transport security Transport Layer Security (TLS) [RFC5246] and other transport security
boundaries. boundaries.
Note that two pre-conditions for this usage scenario are for the Note that two pre-conditions for this usage scenario are for the
protocol to be tunneled and the provisioning server to know the protocol to be tunneled and the provisioning server to know the
correct pre-established manufacturer's key. correct pre-established manufacturer's key.
A.8. End-to-End Protection of Key Material A.8. End-to-End Protection of Key Material
In this scenario, transport layer security does not provide end-to- In this scenario, Transport Layer Security does not provide end-to-
end protection of keying material transported from the provisioning end protection of keying material transported from the provisioning
server to the cryptographic module. For example, TLS may terminate server to the cryptographic module. For example, TLS may terminate
at an application hosted on a PC rather than at the cryptographic at an application hosted on a PC rather than at the cryptographic
module (i.e., the endpoint) located on a data storage device module (i.e., the endpoint) located on a data storage device
[RFC5246]. Mutually authenticated key agreement provides end-to-end [RFC5246]. Mutually authenticated key agreement provides end-to-end
protection, which TLS cannot provide. protection, which TLS cannot provide.
Appendix B. Examples Appendix B. Examples
This appendix contains example messages that illustrate parameters, This appendix contains example messages that illustrate parameters,
encoding, and semantics in four-and two- pass DSKPP exchanges. The encoding, and semantics in four- and two-pass DSKPP exchanges. The
examples are written using XML, and are syntactically correct. MAC examples are written using XML, and are syntactically correct. MAC
and cipher values are fictitious however. This appendix forms an and cipher values are fictitious, however. This appendix forms an
informative part of the document. informative part of the document.
B.1. Trigger Message B.1. Trigger Message
<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<dskpp:KeyProvTrigger Version="1.0" <dskpp:KeyProvTrigger Version="1.0"
xmlns:dskpp="urn:ietf:params:xml:ns:keyprov:dskpp" xmlns:dskpp="urn:ietf:params:xml:ns:keyprov:dskpp"
xmlns:pskc="urn:ietf:params:xml:ns:keyprov:pskc"> xmlns:pskc="urn:ietf:params:xml:ns:keyprov:pskc">
<dskpp:InitializationTrigger> <dskpp:InitializationTrigger>
<dskpp:DeviceIdentifierData> <dskpp:DeviceIdentifierData>
skipping to change at page 78, line 30 skipping to change at page 80, line 48
<dskpp:KeyID>SE9UUDAwMDAwMDAx</dskpp:KeyID> <dskpp:KeyID>SE9UUDAwMDAwMDAx</dskpp:KeyID>
<dskpp:TokenPlatformInfo KeyLocation="Hardware" <dskpp:TokenPlatformInfo KeyLocation="Hardware"
AlgorithmLocation="Software"/> AlgorithmLocation="Software"/>
<dskpp:AuthenticationData> <dskpp:AuthenticationData>
<dskpp:ClientID>31300257</dskpp:ClientID> <dskpp:ClientID>31300257</dskpp:ClientID>
<dskpp:AuthenticationCodeMac> <dskpp:AuthenticationCodeMac>
<dskpp:IterationCount>512</dskpp:IterationCount> <dskpp:IterationCount>512</dskpp:IterationCount>
<dskpp:Mac>4bRJf9xXd3KchKoTenHJiw==</dskpp:Mac> <dskpp:Mac>4bRJf9xXd3KchKoTenHJiw==</dskpp:Mac>
</dskpp:AuthenticationCodeMac> </dskpp:AuthenticationCodeMac>
</dskpp:AuthenticationData> </dskpp:AuthenticationData>
<dskpp:ServerUrl>https://www.somekeyprovservice.com/ <dskpp:ServerUrl>keyprovservice.example.com
</dskpp:ServerUrl> </dskpp:ServerUrl>
</dskpp:InitializationTrigger> </dskpp:InitializationTrigger>
</dskpp:KeyProvTrigger> </dskpp:KeyProvTrigger>
B.2. Four-Pass Protocol B.2. Four-Pass Protocol
B.2.1. <KeyProvClientHello> Without a Preceding Trigger B.2.1. <KeyProvClientHello> without a Preceding Trigger
<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<dskpp:KeyProvClientHello <dskpp:KeyProvClientHello
xmlns:pskc="urn:ietf:params:xml:ns:keyprov:pskc" xmlns:pskc="urn:ietf:params:xml:ns:keyprov:pskc"
xmlns:dskpp="urn:ietf:params:xml:ns:keyprov:dskpp" xmlns:dskpp="urn:ietf:params:xml:ns:keyprov:dskpp"
xmlns:xenc="http://www.w3.org/2001/04/xmlenc#" xmlns:xenc="http://www.w3.org/2001/04/xmlenc#"
xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
Version="1.0"> Version="1.0">
<dskpp:DeviceIdentifierData> <dskpp:DeviceIdentifierData>
<dskpp:DeviceId> <dskpp:DeviceId>
<pskc:Manufacturer>TokenVendorAcme</pskc:Manufacturer> <pskc:Manufacturer>TokenVendorAcme</pskc:Manufacturer>
skipping to change at page 88, line 19 skipping to change at page 90, line 25
MacAlgorithm= MacAlgorithm=
"urn:ietf:params:xml:ns:keyprov:dskpp:prf-sha256"> "urn:ietf:params:xml:ns:keyprov:dskpp:prf-sha256">
GHZ0H6Y+KpxdlVZ7zgcJDiDdqc8Gcmlcf+HQi4EUxYU= GHZ0H6Y+KpxdlVZ7zgcJDiDdqc8Gcmlcf+HQi4EUxYU=
</dskpp:Mac> </dskpp:Mac>
</dskpp:KeyProvServerFinished> </dskpp:KeyProvServerFinished>
B.3.2. Example Using the Key Wrap Method B.3.2. Example Using the Key Wrap Method
The client sends a request that specifies a shared key to protect the The client sends a request that specifies a shared key to protect the
K_TOKEN, and the server responds using the Key Wrap key protection K_TOKEN, and the server responds using the Key Wrap key protection
method. Authentication data in this example is based on an method. Authentication Data in this example is based on an
authentication code rather than a device certificate. Authentication Code rather than a device certificate.
<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<dskpp:KeyProvClientHello <dskpp:KeyProvClientHello
xmlns:pskc="urn:ietf:params:xml:ns:keyprov:pskc" xmlns:pskc="urn:ietf:params:xml:ns:keyprov:pskc"
xmlns:dskpp="urn:ietf:params:xml:ns:keyprov:dskpp" xmlns:dskpp="urn:ietf:params:xml:ns:keyprov:dskpp"
xmlns:xenc="http://www.w3.org/2001/04/xmlenc#" xmlns:xenc="http://www.w3.org/2001/04/xmlenc#"
xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
Version="1.0"> Version="1.0">
<dskpp:DeviceIdentifierData> <dskpp:DeviceIdentifierData>
<dskpp:DeviceId> <dskpp:DeviceId>
skipping to change at page 91, line 46 skipping to change at page 94, line 8
<dskpp:Mac <dskpp:Mac
MacAlgorithm= MacAlgorithm=
"urn:ietf:params:xml:ns:keyprov:dskpp:prf-sha256"> "urn:ietf:params:xml:ns:keyprov:dskpp:prf-sha256">
l53BmSO6qUzoIgbQegimsKk2es+WRpEl0YFqaOp5PGE= l53BmSO6qUzoIgbQegimsKk2es+WRpEl0YFqaOp5PGE=
</dskpp:Mac> </dskpp:Mac>
</dskpp:KeyProvServerFinished> </dskpp:KeyProvServerFinished>
B.3.3. Example Using the Passphrase-Based Key Wrap Method B.3.3. Example Using the Passphrase-Based Key Wrap Method
The client sends a request similar to that in Appendix B.3.1 with The client sends a request similar to that in Appendix B.3.1 with
authentication data based on an authentication code, and the server Authentication Data based on an Authentication Code, and the server
responds using the Passphrase-Based Key Wrap method to encrypt the responds using the Passphrase-Based Key Wrap method to encrypt the
provisioning key (note that the encryption is derived from the provisioning key (note that the encryption is derived from the
password component of the authentication code). The authentication password component of the Authentication Code). The Authentication
data is set in clear text when it is sent over a secure transport Data is set in clear text when it is sent over a secure transport
channel such as TLS [RFC5246]. channel such as TLS [RFC5246].
<?xml version="1.0" encoding="UTF-8" standalone="yes"?> <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<dskpp:KeyProvClientHello <dskpp:KeyProvClientHello
xmlns:pskc="urn:ietf:params:xml:ns:keyprov:pskc" xmlns:pskc="urn:ietf:params:xml:ns:keyprov:pskc"
xmlns:dskpp="urn:ietf:params:xml:ns:keyprov:dskpp" xmlns:dskpp="urn:ietf:params:xml:ns:keyprov:dskpp"
xmlns:xenc="http://www.w3.org/2001/04/xmlenc#" xmlns:xenc="http://www.w3.org/2001/04/xmlenc#"
xmlns:ds="http://www.w3.org/2000/09/xmldsig#" xmlns:ds="http://www.w3.org/2000/09/xmldsig#"
Version="1.0"> Version="1.0">
<dskpp:DeviceIdentifierData> <dskpp:DeviceIdentifierData>
skipping to change at page 95, line 45 skipping to change at page 98, line 7
</dskpp:KeyContainer> </dskpp:KeyContainer>
</dskpp:KeyPackage> </dskpp:KeyPackage>
<dskpp:Mac MacAlgorithm= <dskpp:Mac MacAlgorithm=
"urn:ietf:params:xml:ns:keyprov:dskpp:prf-sha256"> "urn:ietf:params:xml:ns:keyprov:dskpp:prf-sha256">
Jc4VsNODYXgfbDmTn9qQZgcL3cKoa//j/NRT7sTpKOM= Jc4VsNODYXgfbDmTn9qQZgcL3cKoa//j/NRT7sTpKOM=
</dskpp:Mac> </dskpp:Mac>
</dskpp:KeyProvServerFinished> </dskpp:KeyProvServerFinished>
Appendix C. Integration with PKCS #11 Appendix C. Integration with PKCS #11
A DSKPP client that needs to communicate with a connected A DSKPP Client that needs to communicate with a connected
cryptographic module to perform a DSKPP exchange MAY use PKCS #11 cryptographic module to perform a DSKPP exchange MAY use PKCS #11
[PKCS-11] as a programming interface as described herein. This [PKCS-11] as a programming interface as described herein. This
appendix forms an informative part of the document. appendix forms an informative part of the document.
C.1. The 4-pass Variant C.1. The Four-Pass Variant
When performing 4-pass DSKPP with a cryptographic module using the When performing four-pass DSKPP with a cryptographic module using the
PKCS #11 programming interface, the procedure described in PKCS #11 programming interface, the procedure described in
[CT-KIP-P11], Appendix B, is RECOMMENDED. [CT-KIP-P11], Appendix B, is RECOMMENDED.
C.2. The 2-pass Variant C.2. The Two-Pass Variant
A suggested procedure to perform 2-pass DSKPP with a cryptographic A suggested procedure to perform two-pass DSKPP with a cryptographic
module through the PKCS #11 interface using the mechanisms defined in module through the PKCS #11 interface using the mechanisms defined in
[CT-KIP-P11] is as follows: [CT-KIP-P11] is as follows:
a. On the client side, a. On the client side,
1. The client selects a suitable slot and token (e.g., through 1. The client selects a suitable slot and token (e.g., through
use of the <DeviceIdentifier> or the <PlatformInfo> element use of the <DeviceIdentifier> or the <PlatformInfo> element
of the DSKPP trigger message). of the DSKPP trigger message).
2. A nonce R is generated, e.g. by calling C_SeedRandom and
2. A nonce R is generated, e.g., by calling C_SeedRandom and
C_GenerateRandom. C_GenerateRandom.
3. The client sends its first message to the server, including 3. The client sends its first message to the server, including
the nonce R. the nonce R.
b. On the server side, b. On the server side,
1. A generic key K_PROV = K_TOKEN | K_MAC (where '|' denotes 1. A generic key K_PROV = K_TOKEN | K_MAC (where '|' denotes
concatenation) is generated, e.g. by calling C_GenerateKey concatenation) is generated, e.g., by calling C_GenerateKey
(using key type CKK_GENERIC_SECRET). The template for K_PROV (using key type CKK_GENERIC_SECRET). The template for K_PROV
MUST allow it to be exported (but only in wrapped form, i.e. MUST allow it to be exported (but only in wrapped form, i.e.,
CKA_SENSITIVE MUST be set to CK_TRUE and CKA_EXTRACTABLE MUST CKA_SENSITIVE MUST be set to CK_TRUE and CKA_EXTRACTABLE MUST
also be set to CK_TRUE), and also to be used for further key also be set to CK_TRUE), and also to be used for further key
derivation. From K, a token key K_TOKEN of suitable type is derivation. From K, a token key K_TOKEN of suitable type is
derived by calling C_DeriveKey using the PKCS #11 mechanism derived by calling C_DeriveKey using the PKCS #11 mechanism
CKM_EXTRACT_KEY_FROM_KEY and setting the CK_EXTRACT_PARAMS to CKM_EXTRACT_KEY_FROM_KEY and setting the CK_EXTRACT_PARAMS to
the first bit of the generic secret key (i.e. set to 0). the first bit of the generic secret key (i.e., set to 0).
Likewise, a MAC key K_MAC is derived from K_PROV by calling Likewise, a MAC key K_MAC is derived from K_PROV by calling
C_DeriveKey using the CKM_EXTRACT_KEY_FROM_KEY mechanism, C_DeriveKey using the CKM_EXTRACT_KEY_FROM_KEY mechanism,
this time setting CK_EXTRACT_PARAMS to the length of K_PROV this time setting CK_EXTRACT_PARAMS to the length of K_PROV
(in bits) divided by two. (in bits) divided by two.
2. The server wraps K_PROV with either the public key of the 2. The server wraps K_PROV with either the public key of the
DSKPP client or device, the pre-shared secret key, or the DSKPP Client or device, the pre-shared secret key, or the
derived shared secret key by using C_WrapKey. If use of the derived shared secret key by using C_WrapKey. If use of the
DSKPP key wrap algorithm has been negotiated then the DSKPP key wrap algorithm has been negotiated, then the
CKM_KIP_WRAP mechanism MUST be used to wrap K. When calling CKM_KIP_WRAP mechanism MUST be used to wrap K. When calling
C_WrapKey, the hKey handle in the CK_KIP_PARAMS structure C_WrapKey, the hKey handle in the CK_KIP_PARAMS structure
MUST be set to NULL_PTR. The pSeed parameter in the MUST be set to NULL_PTR. The pSeed parameter in the
CK_KIP_PARAMS structure MUST point to the nonce R provided by CK_KIP_PARAMS structure MUST point to the nonce R provided by
the DSKPP client, and the ulSeedLen parameter MUST indicate the DSKPP Client, and the ulSeedLen parameter MUST indicate
the length of R. The hWrappingKey parameter in the call to the length of R. The hWrappingKey parameter in the call to
C_WrapKey MUST be set to refer to the key wrapping key. C_WrapKey MUST be set to refer to the key wrapping key.
3. Next, the server needs to calculate a MAC using K_MAC. If 3. Next, the server needs to calculate a MAC using K_MAC. If
use of the DSKPP MAC algorithm has been negotiated, then the use of the DSKPP MAC algorithm has been negotiated, then the
MAC is calculated by calling C_SignInit with the CKM_KIP_MAC MAC is calculated by calling C_SignInit with the CKM_KIP_MAC
mechanism followed by a call to C_Sign. In the call to mechanism followed by a call to C_Sign. In the call to
C_SignInit, K_MAC MUST be the signature key, the hKey C_SignInit, K_MAC MUST be the signature key, the hKey
parameter in the CK_KIP_PARAMS structure MUST be set to parameter in the CK_KIP_PARAMS structure MUST be set to
NULL_PTR, the pSeed parameter of the CT_KIP_PARAMS structure NULL_PTR, the pSeed parameter of the CT_KIP_PARAMS structure
MUST be set to NULL_PTR, and the ulSeedLen parameter MUST be MUST be set to NULL_PTR, and the ulSeedLen parameter MUST be
skipping to change at page 97, line 19 skipping to change at page 99, line 31
C_SignInit, K_MAC MUST be the signature key, the hKey C_SignInit, K_MAC MUST be the signature key, the hKey
parameter in the CK_KIP_PARAMS structure MUST be set to parameter in the CK_KIP_PARAMS structure MUST be set to
NULL_PTR, the pSeed parameter of the CT_KIP_PARAMS structure NULL_PTR, the pSeed parameter of the CT_KIP_PARAMS structure
MUST be set to NULL_PTR, and the ulSeedLen parameter MUST be MUST be set to NULL_PTR, and the ulSeedLen parameter MUST be
set to zero. In the call to C_Sign, the pData parameter MUST set to zero. In the call to C_Sign, the pData parameter MUST
be set to the concatenation of the string ServerID and the be set to the concatenation of the string ServerID and the
nonce R, and the ulDataLen parameter MUST be set to the nonce R, and the ulDataLen parameter MUST be set to the
length of the concatenated string. The desired length of the length of the concatenated string. The desired length of the
MAC MUST be specified through the pulSignatureLen parameter MAC MUST be specified through the pulSignatureLen parameter
and MUST be set to the length of R. and MUST be set to the length of R.
4. If the server also needs to authenticate its message (due to 4. If the server also needs to authenticate its message (due to
an existing K_TOKEN being replaced), the server MUST an existing K_TOKEN being replaced), the server MUST
calculate a second MAC. Again, if use of the DSKPP MAC calculate a second MAC. Again, if use of the DSKPP MAC
algorithm has been negotiated, then the MAC is calculated by algorithm has been negotiated, then the MAC is calculated by
calling C_SignInit with the CKM_KIP_MAC mechanism followed by calling C_SignInit with the CKM_KIP_MAC mechanism followed by
a call to C_Sign. In this call to C_SignInit, the K_MAC' a call to C_Sign. In this call to C_SignInit, the K_MAC'
existing before this DSKPP protocol run MUST be the signature existing before this DSKPP run MUST be the signature key (the
key (the implementation may specify K_MAC' to be the value of implementation may specify K_MAC' to be the value of the
the K_TOKEN that is being replaced, or a version of K_MAC K_TOKEN that is being replaced, or a version of K_MAC from
from the previous protocol run), the hKey parameter in the the previous protocol run), the hKey parameter in the
CK_KIP_PARAMS structure MUST be set to NULL, the pSeed CK_KIP_PARAMS structure MUST be set to NULL, the pSeed
parameter of the CT_KIP_PARAMS structure MUST be set to parameter of the CT_KIP_PARAMS structure MUST be set to
NULL_PTR, and the ulSeedLen parameter MUST be set to zero. NULL_PTR, and the ulSeedLen parameter MUST be set to zero.
In the call to C_Sign, the pData parameter MUST be set to the In the call to C_Sign, the pData parameter MUST be set to the
concatenation of the string ServerID and the nonce R, and the concatenation of the string ServerID and the nonce R, and the
ulDataLen parameter MUST be set to the length of concatenated ulDataLen parameter MUST be set to the length of concatenated
string. The desired length of the MAC MUST be specified string. The desired length of the MAC MUST be specified
through the pulSignatureLen parameter and MUST be set to the through the pulSignatureLen parameter and MUST be set to the
length of R. length of R.
5. The server sends its message to the client, including the 5. The server sends its message to the client, including the
wrapped key K_TOKEN, the MAC and possibly also the wrapped key K_TOKEN, the MAC and possibly also the
authenticating MAC. authenticating MAC.
c. On the client side, c. On the client side,
1. The client calls C_UnwrapKey to receive a handle to K. After
this, the client calls C_DeriveKey twice: Once to derive 1. The client calls C_UnwrapKey to receive a handle to K. After
this, the client calls C_DeriveKey twice: once to derive
K_TOKEN and once to derive K_MAC. The client MUST use the K_TOKEN and once to derive K_MAC. The client MUST use the
same mechanism (CKM_EXTRACT_KEY_FROM_KEY) and the same same mechanism (CKM_EXTRACT_KEY_FROM_KEY) and the same
mechanism parameters as used by the server above. When mechanism parameters as used by the server above. When
calling C_UnwrapKey and C_DeriveKey, the pTemplate parameter calling C_UnwrapKey and C_DeriveKey, the pTemplate parameter
MUST be used to set additional key attributes in accordance MUST be used to set additional key attributes in accordance
with local policy and as negotiated and expressed in the with local policy and as negotiated and expressed in the
protocol. In particular, the value of the <KeyID> element in protocol. In particular, the value of the <KeyID> element in
the server's response message MAY be used as CKA_ID for the server's response message MAY be used as CKA_ID for
K_TOKEN. The key K_PROV MUST be destroyed after deriving K_TOKEN. The key K_PROV MUST be destroyed after deriving
K_TOKEN and K_MAC. K_TOKEN and K_MAC.
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ulSeedLen MUST be set to 0. The hKey parameter of ulSeedLen MUST be set to 0. The hKey parameter of
C_VerifyInit MUST refer to K_MAC. In the call to C_Verify, C_VerifyInit MUST refer to K_MAC. In the call to C_Verify,
pData MUST be set to the concatenation of the string ServerID pData MUST be set to the concatenation of the string ServerID
and the nonce R, and the ulDataLen parameter MUST be set to and the nonce R, and the ulDataLen parameter MUST be set to
the length of the concatenated string, pSignature to the MAC the length of the concatenated string, pSignature to the MAC
value received from the server, and ulSignatureLen to the value received from the server, and ulSignatureLen to the
length of the MAC. If the MAC does not verify the protocol length of the MAC. If the MAC does not verify the protocol
session ends with a failure. The token MUST be constructed session ends with a failure. The token MUST be constructed
to not "commit" to the new K_TOKEN or the new K_MAC unless to not "commit" to the new K_TOKEN or the new K_MAC unless
the MAC verifies. the MAC verifies.
3. If an authenticating MAC was received (REQUIRED if the new 3. If an authenticating MAC was received (REQUIRED if the new
K_TOKEN will replace an existing key on the token), then it K_TOKEN will replace an existing key on the token), then it
is verified in a similar vein but using the K_MAC' associated is verified in a similar vein but using the K_MAC' associated
with this server and existing before the protocol run (the with this server and existing before the protocol run (the
implementation may specify K_MAC' to be the value of the implementation may specify K_MAC' to be the value of the
K_TOKEN that is being replaced, or a version of K_MAC from K_TOKEN that is being replaced, or a version of K_MAC from
the previous protocol run). Again, if the MAC does not the previous protocol run). Again, if the MAC does not
verify the protocol session ends with a failure, and the verify the protocol session ends with a failure, and the
token MUST be constructed no to "commit" to the new K_TOKEN token MUST be constructed not to "commit" to the new K_TOKEN
or the new K_MAC unless the MAC verifies. or the new K_MAC unless the MAC verifies.
Appendix D. Example of DSKPP-PRF Realizations Appendix D. Example of DSKPP-PRF Realizations
D.1. Introduction D.1. Introduction
This example appendix defines DSKPP-PRF in terms of AES [FIPS197-AES] This example appendix defines DSKPP-PRF in terms of AES [FIPS197-AES]
and HMAC [RFC2104]. This appendix forms a normative part of the and HMAC [RFC2104]. This appendix forms a normative part of the
document. document.
skipping to change at page 100, line 5 skipping to change at page 102, line 29
The function F is defined in terms of the CMAC construction from The function F is defined in terms of the CMAC construction from
[NIST-SP800-38B], using AES as the block cipher: [NIST-SP800-38B], using AES as the block cipher:
F (k, s, i) = CMAC-AES (k, INT (i) || s) F (k, s, i) = CMAC-AES (k, INT (i) || s)
where INT (i) is a four-octet encoding of the integer i, most where INT (i) is a four-octet encoding of the integer i, most
significant octet first, and the output length of CMAC is set to significant octet first, and the output length of CMAC is set to
bLen. bLen.
Concatenate the blocks and extract the first dsLen octets to product Concatenate the blocks and extract the first dsLen octets to produce
the desired data string DS: the desired data string DS:
DS = B1 || B2 || ... || Bn<0..j-1> DS = B1 || B2 || ... || Bn<0..j-1>
Output the derived data DS. Output the derived data DS.
D.2.3. Example D.2.3. Example
If we assume that dsLen = 16, then: If we assume that dsLen = 16, then:
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The function F is defined in terms of the HMAC construction from The function F is defined in terms of the HMAC construction from
[RFC2104], using SHA-256 as the digest algorithm: [RFC2104], using SHA-256 as the digest algorithm:
F (k, s, i) = HMAC-SHA256 (k, INT (i) || s) F (k, s, i) = HMAC-SHA256 (k, INT (i) || s)
where INT (i) is a four-octet encoding of the integer i, most where INT (i) is a four-octet encoding of the integer i, most
significant octet first, and the output length of HMAC is set to significant octet first, and the output length of HMAC is set to
bLen. bLen.
Concatenate the blocks and extract the first dsLen octets to product Concatenate the blocks and extract the first dsLen octets to produce
the desired data string DS: the desired data string DS:
DS = B1 || B2 || ... || Bn<0..j-1> DS = B1 || B2 || ... || Bn<0..j-1>
Output the derived data DS. Output the derived data DS.
D.3.3. Example D.3.3. Example
If we assume that sLen = 256 (two 128-octet long values) and dsLen = If we assume that sLen = 256 (two 128-octet long values) and dsLen =
16, then: 16, then:
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That is, the result will be the first 16 octets of the HMAC output. That is, the result will be the first 16 octets of the HMAC output.
Authors' Addresses Authors' Addresses
Andrea Doherty Andrea Doherty
RSA, The Security Division of EMC RSA, The Security Division of EMC
174 Middlesex Turnpike 174 Middlesex Turnpike
Bedford, MA 01730 Bedford, MA 01730
USA USA
Email: andrea.doherty@rsa.com EMail: andrea.doherty@rsa.com
Mingliang Pei Mingliang Pei
VeriSign, Inc. VeriSign, Inc.
487 E. Middlefield Road 487 E. Middlefield Road
Mountain View, CA 94043 Mountain View, CA 94043
USA USA
Email: mpei@verisign.com EMail: mpei@verisign.com
Salah Machani Salah Machani
Diversinet Corp. Diversinet Corp.
2225 Sheppard Avenue East, Suite 1801 2225 Sheppard Avenue East, Suite 1801
Toronto, Ontario M2J 5C2 Toronto, Ontario M2J 5C2
Canada Canada
Email: smachani@diversinet.com EMail: smachani@diversinet.com
Magnus Nystrom Magnus Nystrom
Microsoft Corp. Microsoft Corp.
One Microsoft Way One Microsoft Way
Redmond, WA 98052 Redmond, WA 98052
USA USA
Email: mnystrom@microsoft.com EMail: mnystrom@microsoft.com
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