--- 1/draft-ietf-lamps-cms-shakes-05.txt 2019-01-14 08:13:21.931512444 -0800 +++ 2/draft-ietf-lamps-cms-shakes-06.txt 2019-01-14 08:13:22.003514183 -0800 @@ -1,20 +1,20 @@ -LAMPS WG Q. Dang -Internet-Draft NIST -Intended status: Standards Track P. Kampanakis -Expires: June 21, 2019 Cisco Systems - December 18, 2018 +LAMPS WG P. Kampanakis +Internet-Draft Cisco Systems +Intended status: Standards Track Q. Dang +Expires: July 18, 2019 NIST + January 14, 2019 Use of the SHAKE One-way Hash Functions in the Cryptographic Message Syntax (CMS) - draft-ietf-lamps-cms-shakes-05 + draft-ietf-lamps-cms-shakes-06 Abstract This document describes the conventions for using the SHAKE family of hash functions with the Cryptographic Message Syntax (CMS) as one-way hash functions with the RSA Probabilistic signature and ECDSA signature algorithms, as message digests and message authentication codes. The conventions for the associated signer public keys in CMS are also described. @@ -26,63 +26,67 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on June 21, 2019. + This Internet-Draft will expire on July 18, 2019. Copyright Notice - Copyright (c) 2018 IETF Trust and the persons identified as the + Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 + 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 3. Identifiers . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Use in CMS . . . . . . . . . . . . . . . . . . . . . . . . . 6 4.1. Message Digests . . . . . . . . . . . . . . . . . . . . . 6 4.2. Signatures . . . . . . . . . . . . . . . . . . . . . . . 6 - 4.2.1. RSASSA-PSS Signatures . . . . . . . . . . . . . . . . 6 - 4.2.2. Deterministic ECDSA Signatures . . . . . . . . . . . 7 + 4.2.1. RSASSA-PSS Signatures . . . . . . . . . . . . . . . . 7 + 4.2.2. ECDSA Signatures . . . . . . . . . . . . . . . . . . 7 4.3. Public Keys . . . . . . . . . . . . . . . . . . . . . . . 8 4.4. Message Authentication Codes . . . . . . . . . . . . . . 8 - 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 + 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 - 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 - 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 + 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10 + 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 8.1. Normative References . . . . . . . . . . . . . . . . . . 10 8.2. Informative References . . . . . . . . . . . . . . . . . 11 Appendix A. ASN.1 Module . . . . . . . . . . . . . . . . . . . . 12 - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 1. Change Log [ EDNOTE: Remove this section before publication. ] + o draft-ietf-lamps-pkix-shake-06: + + * Incorporated Eric's suggestion from WGLC. + o draft-ietf-lamps-cms-shake-05: * Added informative references. * Updated ASN.1 so it compiles. * Updated IANA considerations. o draft-ietf-lamps-cms-shake-04: @@ -143,32 +147,32 @@ This specification describes the use of the SHAKE128 and SHAKE256 specified in [SHA3] as new hash functions in CMS. In addition, it describes the use of these functions with the RSASSA-PSS signature algorithm [RFC8017] and the Elliptic Curve Digital Signature Algorithm (ECDSA) [X9.62] with the CMS signed-data content type. In the SHA-3 family, two extendable-output functions (SHAKEs), SHAKE128 and SHAKE256, are defined. Four other hash function instances, SHA3-224, SHA3-256, SHA3-384, and SHA3-512 are also defined but are out of scope for this document. A SHAKE is a - variable length hash function. The output length, in bits, of a - SHAKE is defined by the d parameter. The corresponding collision and - second preimage resistance strengths for SHAKE128 are min(d/2,128) - and min(d,128) bits respectively. And, the corresponding collision - and second preimage resistance strengths for SHAKE256 are - min(d/2,256) and min(d,256) bits respectively. + variable length hash function defined as SHAKE(M, d) where the output + is a d-bits long digest of message M. The corresponding collision + and second preimage resistance strengths for SHAKE128 are + min(d/2,128) and min(d,128) bits respectively. And, the + corresponding collision and second preimage resistance strengths for + SHAKE256 are min(d/2,256) and min(d,256) bits respectively. A SHAKE can be used in CMS as the message digest function (to hash - the message to be signed) in RSASSA-PSS and deterministic ECDSA, - message authentication code and as the mask generating function in - RSASSA-PSS. This specification describes the identifiers for SHAKEs - to be used in CMS and their meaning. + the message to be signed) in RSASSA-PSS and ECDSA, message + authentication code and as the mask generating function in RSASSA- + PSS. This specification describes the identifiers for SHAKEs to be + used in CMS and their meaning. 2.1. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 3. Identifiers @@ -213,42 +217,42 @@ id-ecdsa-with-SHAKE128 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistAlgorithm(4) 3 TBD } id-ecdsa-with-SHAKE256 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistAlgorithm(4) 3 TBD } [ EDNOTE: "TBD" will be specified by NIST. ] - The parameters for the four RSASSA-PSS and deterministic ECDSA - identifiers MUST be absent. That is, each identifier SHALL be a - SEQUENCE of one component, the OID. + The parameters for the four RSASSA-PSS and ECDSA identifiers MUST be + absent. That is, each identifier SHALL be a SEQUENCE of one + component, the OID. Two new object identifiers for KMACs using SHAKE128 and SHAKE256 are - define elow. + defined below. id-KmacWithSHAKE128 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistAlgorithm(4) 2 19 } id-KmacWithSHAKE256 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistAlgorithm(4) 2 20 } The parameters for id-KmacWithSHAKE128 and id-KmacWithSHAKE256 MUST be absent. That is, each identifier SHALL be a SEQUENCE of one component, the OID. Section 4.1, Section 4.2.1, Section 4.2.2 and Section 4.4 specify the required output length for each use of SHAKE128 or SHAKE256 in - message digests, RSASSA-PSS, determinstic ECDSA and KMAC. + message digests, RSASSA-PSS, ECDSA and KMAC. 4. Use in CMS 4.1. Message Digests The id-shake128-len and id-shake256-len OIDs (Section 3) can be used as the digest algorithm identifiers located in the SignedData, SignerInfo, DigestedData, and the AuthenticatedData digestAlgorithm fields in CMS [RFC5652]. The encoding MUST omit the parameters field and the output size, d, for the SHAKE128 or SHAKE256 message digest @@ -260,23 +264,23 @@ values are input to signature algorithms. The digest algorithm MUST be the same as the message hash algorithms used in signatures. 4.2. Signatures In CMS, signature algorithm identifiers are located in the SignerInfo signatureAlgorithm field of SignedData content type and countersignature attribute. Signature values are located in the SignerInfo signature field of SignedData and countersignature. - Conforming implementations that process RSASSA-PSS and deterministic - ECDSA with SHAKE signatures when processing CMS data MUST recognize - the corresponding OIDs specified in Section 3. + Conforming implementations that process RSASSA-PSS and ECDSA with + SHAKE signatures when processing CMS data MUST recognize the + corresponding OIDs specified in Section 3. 4.2.1. RSASSA-PSS Signatures The RSASSA-PSS algorithm is defined in [RFC8017]. When id-RSASSA- PSS-SHAKE128 or id-RSASSA-PSS-SHAKE256 specified in Section 3 is used, the encoding MUST omit the parameters field. That is, the AlgorithmIdentifier SHALL be a SEQUENCE of one component, id-RSASSA- PSS-SHAKE128 or id-RSASSA-PSS-SHAKE256. [RFC4055] defines RSASSA- PSS-params that are used to define the algorithms and inputs to the algorithm. This specification does not use parameters because the @@ -290,73 +294,83 @@ 64 bytes respectively. The mask generation function takes an octet string of variable length and a desired output length as input, and outputs an octet string of the desired length. In RSASSA-PSS with SHAKES, the SHAKEs MUST be used natively as the MGF function, instead of the MGF1 algorithm that uses the hash function in multiple iterations as specified in Section B.2.1 of [RFC8017]. In other words, the MGF is defined as the SHAKE128 or SHAKE256 output of the mgfSeed for id-RSASSA-PSS- SHAKE128 and id-RSASSA-PSS-SHAKE256 respectively. The mgfSeed is the - seed from which mask is generated, an octet string [RFC8017]. The - output length is (n - 264)/8 or (n - 520)/8 bytes respectively, where - n is the RSA modulus in bits. For example, when RSA modulus n is - 2048, the output length of SHAKE128 or SHAKE256 as the MGF will be - 223 or 191-bits when id-RSASSA-PSS-SHAKE128 or id-RSASSA-PSS-SHAKE256 - is used respectively. + seed from which mask is generated, an octet string [RFC8017]. As + explained in Step 9 of section 9.1.1 of [RFC8017], the output length + of the MGF is emLen - hLen - 1 bytes. emLen is the maximum message + length ceil((n-1)/8), where n is the RSA modulus in bits. hLen is 32 + and 64-bytes for id-RSASSA-PSS-SHAKE128 and id-RSASSA-PSS-SHAKE256 + respectively. Thus when SHAKE is used as the MGF, the SHAKE output + length maskLen is (n - 264) or (n - 520) bits respectively. For + example, when RSA modulus n is 2048, the output length of SHAKE128 or + SHAKE256 as the MGF will be 1784 or 1528-bits when id-RSASSA-PSS- + SHAKE128 or id-RSASSA-PSS-SHAKE256 is used respectively. The RSASSA-PSS saltLength MUST be 32 or 64 bytes respectively. Finally, the trailerField MUST be 1, which represents the trailer field with hexadecimal value 0xBC [RFC8017]. -4.2.2. Deterministic ECDSA Signatures +4.2.2. ECDSA Signatures The Elliptic Curve Digital Signature Algorithm (ECDSA) is defined in [X9.62]. When the id-ecdsa-with-SHAKE128 or id-ecdsa-with-SHAKE256 (specified in Section 3) algorithm identifier appears, the respective SHAKE function is used as the hash. The encoding MUST omit the parameters field. That is, the AlgorithmIdentifier SHALL be a SEQUENCE of one component, the OID id-ecdsa-with-SHAKE128 or id- ecdsa-with-SHAKE256. For simplicity and compliance with the ECDSA standard specification, the output size of the hash function must be explicitly determined. The output size, d, for SHAKE128 or SHAKE256 used in ECDSA MUST be 256 or 512 bits respectively. - Conforming implementations that generate ECDSA with SHAKE signatures - in CMS MUST generate such signatures with a deterministicly - generated, non-random k in accordance with all the requirements - specified in [RFC6979]. They MAY also generate such signatures in - accordance with all other recommendations in [X9.62] or [SEC1] if - they have a stated policy that requires conformance to these - standards. + It is RECOMMENDED that conforming implementations that generate ECDSA + with SHAKE signatures in CMS generate such signatures with a + deterministically generated, non-random k in accordance with all the + requirements specified in [RFC6979]. They MAY also generate such + signatures in accordance with all other recommendations in [X9.62] or + [SEC1] if they have a stated policy that requires conformance to + these standards. 4.3. Public Keys In CMS, the signer's public key algorithm identifiers are located in - the OriginatorPublicKey's algorithm attribute. + the OriginatorPublicKey's algorithm attribute. The conventions and + encoding for RSASSA-PSS and ECDSA public keys algorithm identifiers + are as specified in Section 2.3 of [RFC3279], Section 3.1 of + [RFC4055] and Section 2.1 of [RFC5480]. - Conforming implementations MUST specify the algorithms explicitly by - using the OIDs specified in Section 3 when encoding RSASSA-PSS with - SHAKE public keys in CMS messages. The conventions and encoding for - RSASSA-PSS and ECDSA public keys algorithm identifiers are as - specified in Section 2.3 of [RFC3279], Section 3.1 of [RFC4055] and - Section 2.1 of [RFC5480]. + Traditionally, the rsaEncryption object identifier is used to + identify RSA public keys. The rsaEncryption object identifier + continues to identify the public key when the RSA private key owner + does not wish to limit the use of the public key exclusively to + RSASSA-PSS with SHAKEs. When the RSA private key owner wishes to + limit the use of the public key exclusively to RSASSA-PSS, the + AlgorithmIdentifier for RSASSA-PSS defined in Section 3 SHOULD be + used as the algorithm attribute in the OriginatorPublicKey sequence. + Conforming client implementations that process RSASSA-PSS with SHAKE + public keys in CMS message MUST recognize the corresponding OIDs in + Section 3. - When the RSA private key owner wishes to limit the use of the public - key exclusively to RSASSA-PSS, the AlgorithmIdentifier for RSASSA-PSS - defined in Section 3 can be used as the algorithm attribute in the - OriginatorPublicKey sequence. The identifier parameters, as - explained in Section 3, MUST be absent. The RSASSA-PSS algorithm - functions and output lengths are the same as defined in - Section 4.2.1. + Conforming implementations MUST specify and process the algorithms + explicitly by using the OIDs specified in Section 3 when encoding + ECDSA with SHAKE public keys in CMS messages. + + The identifier parameters, as explained in Section 3, MUST be absent. 4.4. Message Authentication Codes KMAC message authentication code (KMAC) is specified in [SP800-185]. In CMS, KMAC algorithm identifiers are located in the AuthenticatedData macAlgorithm field. The KMAC values are located in the AuthenticatedData mac field. When the id-KmacWithSHAKE128 or id-KmacWithSHAKE256 algorithm identifier is used as the MAC algorithm identifier, the parameters @@ -371,63 +385,63 @@ an empty string, and L, the integer representing the requested output length in bits, is 256 or 512 for KmacWithSHAKE128 or KmacWithSHAKE256 respectively in this specification. 5. IANA Considerations One object identifier for the ASN.1 module in Appendix A was assigned in the SMI Security for S/MIME Module Identifiers (1.2.840.113549.1.9.16.0) registry: - CMSAlgsForSHAKE-2018 { { iso(1) member-body(2) us(840) + CMSAlgsForSHAKE-2019 { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) modules(0) - id-mod-cms-shakes(TBD) } + id-mod-cms-shakes-2019(TBD) } 6. Security Considerations The SHAKEs are deterministic functions. Like any other deterministic function, executing each function with the same input multiple times will produce the same output. Therefore, users should not expect unrelated outputs (with the same or different output lengths) from excuting a SHAKE function with the same input multiple times. The shorter one of any 2 outputs produced from a SHAKE with the same input is a prefix of the longer one. It is a similar situation as truncating a 512-bit output of SHA-512 by taking its 256 left-most bits. These 256 left-most bits are a prefix of the 512-bit output. - Implementations must protect the signer's private key. Compromise of - the signer's private key permits masquerade. - When more than two parties share the same message-authentication key, data origin authentication is not provided. Any party that knows the message-authentication key can compute a valid MAC, therefore the content could originate from any one of the parties. - Implementers should be aware that cryptographic algorithms may become - weaker with time. As new cryptanalysis techniques are developed and - computing power increases, the work factor or time required to break - a particular cryptographic algorithm may decrease. Therefore, - cryptographic algorithm implementations should be modular allowing - new algorithms to be readily inserted. That is, implementers should - be prepared to regularly update the set of algorithms in their - implementations. + When using ECDSA with SHAKEs, the ECDSA curve order SHOULD be chosen + in line with the SHAKE output length. NIST has defined appropriate + use of the hash functions in terms of the algorithm strengths and + expected time frames for secure use in Special Publications (SPs) + [SP800-78-4] and [SP800-107]. These documents can be used as guides + to choose appropriate key sizes for various security scenarios. In + the context of this document id-ecdsa-with-shake128 is RECOMMENDED + for curves with group order of 256-bits. id-ecdsa-with-shake256 is + RECOMMENDED for curves with group order of 384-bits or more. 7. Acknowledgements This document is based on Russ Housley's draft [I-D.housley-lamps-cms-sha3-hash]. It replaces SHA3 hash functions by SHAKE128 and SHAKE256 as the LAMPS WG agreed. The authors would like to thank Russ Housley for his guidance and - very valuable contributions with the ASN.1 module. + very valuable contributions with the ASN.1 module. Valuable feedback + was also provided by Eric Rescorla. 8. References + 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC4055] Schaad, J., Kaliski, B., and R. Housley, "Additional Algorithms and Identifiers for RSA Cryptography for use in the Internet X.509 Public Key Infrastructure Certificate @@ -502,33 +516,47 @@ [SEC1] Standards for Efficient Cryptography Group, "SEC 1: Elliptic Curve Cryptography", May 2009, . [shake-nist-oids] National Institute of Standards and Technology, "Computer Security Objects Register", October 2017, . + [SP800-107] + National Institute of Standards and Technology (NIST), + "SP800-107: Recommendation for Applications Using Approved + Hash Algorithms", May 2014, + . + + [SP800-78-4] + National Institute of Standards and Technology (NIST), + "SP800-78-4: Cryptographic Algorithms and Key Sizes for + Personal Identity Verification", May 2014, + . + [X9.62] American National Standard for Financial Services (ANSI), "X9.62-2005 Public Key Cryptography for the Financial Services Industry: The Elliptic Curve Digital Signature Standard (ECDSA)", November 2005. Appendix A. ASN.1 Module This appendix includes the ASN.1 modules for SHAKEs in CMS. This module includes some ASN.1 from other standards for reference. - CMSAlgsForSHAKE-2018 { iso(1) member-body(2) us(840) + CMSAlgsForSHAKE-2019 { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) modules(0) - id-mod-cms-shakes(TBD) } + id-mod-cms-shakes-2019(TBD) } DEFINITIONS EXPLICIT TAGS ::= BEGIN -- EXPORTS ALL; IMPORTS DIGEST-ALGORITHM, MAC-ALGORITHM, SMIME-CAPS @@ -591,41 +619,45 @@ -- id-RSASSA-PSS-SHAKE128 OBJECT IDENTIFIER ::= { TBD } id-RSASSA-PSS-SHAKE256 OBJECT IDENTIFIER ::= { TBD } -- When the id-RSASSA-PSS-* algorithm identifiers are used -- for a public key or signature in CMS, the AlgorithmIdentifier -- parameters field MUST be absent. The message digest algorithm -- used in RSASSA-PSS MUST be SHAKE128 or SHAKE256 with a 32 or -- 64 byte outout length respectively. The mask generating -- function MUST be SHAKE128 or SHAKE256 with an output length - -- of (n - 264)/8 or (n - 520)/8 bytes respectively, where n + -- of (n - 264) or (n - 520) bits respectively, where n -- is the RSA modulus in bits. The RSASSA-PSS saltLength MUST - -- be 32 or 64 bytes respectively. In both cases, the RSA - -- public key, MUST be encoded using the RSAPublicKey type. + -- be 32 or 64 bytes respectively. The trailerField MUST be 1, + -- which represents the trailer field with hexadecimal value + -- 0xBC. Regardless of id-RSASSA-PSS-* or rsaEncryption being + -- used as the AlgorithmIdentifier of the OriginatorPublicKey, + -- the RSA public key MUST be encoded using the RSAPublicKey + -- type. -- From RFC4055, for reference. -- RSAPublicKey ::= SEQUENCE { -- modulus INTEGER, -- -- n -- publicExponent INTEGER } -- -- e id-ecdsa-with-shake128 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistAlgorithm(4) sigAlgs(3) TBD } id-ecdsa-with-shake256 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistAlgorithm(4) sigAlgs(3) TBD } -- When the id-ecdsa-with-shake* algorithm identifiers are -- used in CMS, the AlgorithmIdentifier parameters field - -- MUST be absent and the signature algorithm should - -- Deterministric ECDSA [RFC6979]. The message digest MUST + -- MUST be absent and the signature algorithm should be + -- deterministric ECDSA [RFC6979]. The message digest MUST -- be SHAKE128 or SHAKE256 with a 32 or 64 byte outout -- length respectively. In both cases, the ECDSA public key, -- MUST be encoded using the id-ecPublicKey type. -- From RFC5480, for reference. -- id-ecPublicKey OBJECT IDENTIFIER ::= { -- iso(1) member-body(2) us(840) ansi-X9-62(10045) keyType(2) 1 } -- The id-ecPublicKey parameters must be absent or present -- and are defined as -- ECParameters ::= CHOICE { -- namedCurve OBJECT IDENTIFIER @@ -687,21 +719,21 @@ hashAlgs(2) 20 } KMACwithSHAKE256-params ::= SEQUENCE { kMACOutputLength INTEGER DEFAULT 512, -- Output length in bits customizationString OCTET STRING DEFAULT ''H } END Authors' Addresses + Panos Kampanakis + Cisco Systems + + Email: pkampana@cisco.com + Quynh Dang NIST 100 Bureau Drive Gaithersburg, MD 20899 Email: quynh.Dang@nist.gov - - Panos Kampanakis - Cisco Systems - - Email: pkampana@cisco.com