draft-ietf-lamps-crmf-update-algs-02.txt   draft-ietf-lamps-crmf-update-algs-03.txt 
Network Working Group R. Housley Network Working Group R. Housley
Internet-Draft Vigil Security Internet-Draft Vigil Security
Updates: 4211 (if approved) 21 December 2020 Updates: 4211 (if approved) 29 January 2021
Intended status: Standards Track Intended status: Standards Track
Expires: 24 June 2021 Expires: 2 August 2021
Algorithm Requirements Update to the Internet X.509 Public Key Algorithm Requirements Update to the Internet X.509 Public Key
Infrastructure Certificate Request Message Format (CRMF) Infrastructure Certificate Request Message Format (CRMF)
draft-ietf-lamps-crmf-update-algs-02 draft-ietf-lamps-crmf-update-algs-03
Abstract Abstract
This document updates the cryptographic algorithm requirements for This document updates the cryptographic algorithm requirements for
the Password-Based Message Authentication Code in the Internet X.509 the Password-Based Message Authentication Code in the Internet X.509
Public Key Infrastructure Certificate Request Message Format (CRMF) Public Key Infrastructure Certificate Request Message Format (CRMF)
specified in RFC 4211. specified in RFC 4211.
Status of This Memo Status of This Memo
skipping to change at page 1, line 35 skipping to change at page 1, line 35
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on 24 June 2021. This Internet-Draft will expire on 2 August 2021.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Password-Based Message Authentication Code . . . . . . . . . 2 3. Signature Key POP . . . . . . . . . . . . . . . . . . . . . . 2
3.1. Introduction Paragraph . . . . . . . . . . . . . . . . . 2 4. Password-Based Message Authentication Code . . . . . . . . . 3
3.2. One-Way Function . . . . . . . . . . . . . . . . . . . . 3 4.1. Introduction Paragraph . . . . . . . . . . . . . . . . . 3
3.3. Iteration Count . . . . . . . . . . . . . . . . . . . . . 3 4.2. One-Way Function . . . . . . . . . . . . . . . . . . . . 3
3.4. MAC Algorithm . . . . . . . . . . . . . . . . . . . . . . 4 4.3. Iteration Count . . . . . . . . . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 4.4. MAC Algorithm . . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 5 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
7.1. Normative References . . . . . . . . . . . . . . . . . . 6 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.2. Informative References . . . . . . . . . . . . . . . . . 7 8.1. Normative References . . . . . . . . . . . . . . . . . . 6
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7 8.2. Informative References . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction 1. Introduction
This document updates the cryptographic algorithm requirements for This document updates the cryptographic algorithm requirements for
the Password-Based Message Authentication Code (MAC) in the Internet the Password-Based Message Authentication Code (MAC) in the Internet
X.509 Public Key Infrastructure Certificate Request Message Format X.509 Public Key Infrastructure Certificate Request Message Format
(CRMF) [RFC4211]. The algorithms specified in [RFC4211] were (CRMF) [RFC4211]. The algorithms specified in [RFC4211] were
appropriate in 2005; however, these algorithms are no longer appropriate in 2005; however, these algorithms are no longer
considered the best choices. This update specifies algorithms that considered the best choices. This update specifies algorithms that
are more appropriate today. are more appropriate today.
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
3. Password-Based Message Authentication Code 3. Signature Key POP
Section 4.1 of [RFC4211] specifies the Proof-of-Possession (POP)
processing. This section is updated to explicitly allow the use of
the PBMAC1 algorithm presented in Section 7.1 of [RFC8018].
OLD:
algId identifies the algorithm used to compute the MAC value. All
implementations MUST support id-PasswordBasedMAC. The details on
this algorithm are presented in section 4.4
NEW:
algId identifies the algorithm used to compute the MAC value. All
implementations MUST support id-PasswordBasedMAC as presented in
Section 4.4 of this document. Implementations MAY also support
PBMAC1 presented in Section 7.1 of [RFC8018].
4. Password-Based Message Authentication Code
Section 4.4 of [RFC4211] specifies a Password-Based MAC that relies Section 4.4 of [RFC4211] specifies a Password-Based MAC that relies
on a one-way function to compute a symmetric key from the password on a one-way function to compute a symmetric key from the password
and a MAC algorithm. This section specifies algorithm requirements and a MAC algorithm. This section specifies algorithm requirements
for the one-way function and the MAC algorithm. for the one-way function and the MAC algorithm.
3.1. Introduction Paragraph 4.1. Introduction Paragraph
Add guidance about limiting the use of the password. Add guidance about limiting the use of the password.
OLD: OLD:
This MAC algorithm was designed to take a shared secret (a This MAC algorithm was designed to take a shared secret (a
password) and use it to compute a check value over a piece of password) and use it to compute a check value over a piece of
information. The assumption is that, without the password, the information. The assumption is that, without the password, the
correct check value cannot be computed. The algorithm computes correct check value cannot be computed. The algorithm computes
the one-way function multiple times in order to slow down any the one-way function multiple times in order to slow down any
skipping to change at page 3, line 22 skipping to change at page 3, line 41
NEW: NEW:
This MAC algorithm was designed to take a shared secret (a This MAC algorithm was designed to take a shared secret (a
password) and use it to compute a check value over a piece of password) and use it to compute a check value over a piece of
information. The assumption is that, without the password, the information. The assumption is that, without the password, the
correct check value cannot be computed. The algorithm computes correct check value cannot be computed. The algorithm computes
the one-way function multiple times in order to slow down any the one-way function multiple times in order to slow down any
dictionary attacks against the password value. The password used dictionary attacks against the password value. The password used
to compute this MAC SHOULD NOT be used for any other purpose. to compute this MAC SHOULD NOT be used for any other purpose.
3.2. One-Way Function 4.2. One-Way Function
Change the paragraph describing the "owf" as follows: Change the paragraph describing the "owf" as follows:
OLD: OLD:
owf identifies the algorithm and associated parameters used to owf identifies the algorithm and associated parameters used to
compute the key used in the MAC process. All implementations MUST compute the key used in the MAC process. All implementations MUST
support SHA-1. support SHA-1.
NEW: NEW:
owf identifies the algorithm and associated parameters used to owf identifies the algorithm and associated parameters used to
compute the key used in the MAC process. All implementations MUST compute the key used in the MAC process. All implementations MUST
support SHA-256 [SHS]. support SHA-256 [SHS].
3.3. Iteration Count 4.3. Iteration Count
Update the guidance on appropriate iteration count values. Update the guidance on appropriate iteration count values.
OLD: OLD:
iterationCount identifies the number of times the hash is applied iterationCount identifies the number of times the hash is applied
during the key computation process. The iterationCount MUST be a during the key computation process. The iterationCount MUST be a
minimum of 100. Many people suggest using values as high as 1000 minimum of 100. Many people suggest using values as high as 1000
iterations as the minimum value. The trade off here is between iterations as the minimum value. The trade off here is between
protection of the password from attacks and the time spent by the protection of the password from attacks and the time spent by the
server processing all of the different iterations in deriving server processing all of the different iterations in deriving
passwords. Hashing is generally considered a cheap operation but passwords. Hashing is generally considered a cheap operation but
this may not be true with all hash functions in the future. this may not be true with all hash functions in the future.
NEW: NEW:
iterationCount identifies the number of times the hash is applied iterationCount identifies the number of times the hash is applied
during the key computation process. The iterationCount MUST be a during the key computation process. The iterationCount MUST be a
minimum of 100; however, the iterationCount SHOULD be as large as minimum of 100; however, the iterationCount SHOULD be as large as
server performance will allow, typically at least 10,000 server performance will allow, typically at least 10,000 [DIGALM].
[NISTSP800-63B]. There is a trade off between protection of the There is a trade off between protection of the password from
password from attacks and the time spent by the server processing attacks and the time spent by the server processing the
the iterations. A lower iteration count can be used, if automated iterations. As part of that tradeoff, an iteration count smaller
generation produces shared secrets with high entropy. than 10,000 can be used when automated generation produces shared
secrets with high entropy.
3.4. MAC Algorithm 4.4. MAC Algorithm
Change the paragraph describing the "mac" as follows: Change the paragraph describing the "mac" as follows:
OLD: OLD:
mac identifies the algorithm and associated parameters of the MAC mac identifies the algorithm and associated parameters of the MAC
function to be used. All implementations MUST support HMAC-SHA1 function to be used. All implementations MUST support HMAC-SHA1
[HMAC]. All implementations SHOULD support DES-MAC and Triple- [HMAC]. All implementations SHOULD support DES-MAC and Triple-
DES-MAC [PKCS11]. DES-MAC [PKCS11].
skipping to change at page 4, line 42 skipping to change at page 5, line 18
with a 128 bit key. with a 128 bit key.
For convenience, the identifiers for these two algorithms are For convenience, the identifiers for these two algorithms are
repeated here. repeated here.
The algorithm identifier for HMAC-SHA256 is defined in [RFC4231]: The algorithm identifier for HMAC-SHA256 is defined in [RFC4231]:
id-hmacWithSHA256 OBJECT IDENTIFIER ::= { iso(1) member-body(2) id-hmacWithSHA256 OBJECT IDENTIFIER ::= { iso(1) member-body(2)
us(840) rsadsi(113549) digestAlgorithm(2) 9 } us(840) rsadsi(113549) digestAlgorithm(2) 9 }
When this The algorithm identifier is used, the parameters SHOULD be When this algorithm identifier is used, the parameters SHOULD be
present. When present, the parameters MUST contain a type of NULL. present. When present, the parameters MUST contain a type of NULL.
The algorithm identifier for AES-GMAC [AES][GMAC] with a 128-bit key The algorithm identifier for AES-GMAC [AES][GMAC] with a 128-bit key
is defined in [I-D.housley-lamps-cms-aes-mac-alg]: is defined in [I-D.ietf-lamps-cms-aes-gmac-alg]:
id-aes128-GMAC OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) id-aes128-GMAC OBJECT IDENTIFIER ::= { joint-iso-itu-t(2)
country(16) us(840) organization(1) gov(101) csor(3) country(16) us(840) organization(1) gov(101) csor(3)
nistAlgorithm(4) aes(1) 9 } nistAlgorithm(4) aes(1) 9 }
When this algorithm identifier is used, the parameters MUST be When this algorithm identifier is used, the parameters MUST be
present, and the parameters MUST contain the GMACParameters structure present, and the parameters MUST contain the GMACParameters structure
as follows: as follows:
GMACParameters ::= SEQUENCE { GMACParameters ::= SEQUENCE {
nonce OCTET STRING, -- recommended size is 12 octets nonce OCTET STRING,
length MACLength DEFAULT 12 } length MACLength DEFAULT 12 }
MACLength ::= INTEGER (12 | 13 | 14 | 15 | 16) MACLength ::= INTEGER (12 | 13 | 14 | 15 | 16)
The GMACParameters nonce parameter is the GMAC initialization vector. The GMACParameters nonce parameter is the GMAC initialization vector.
The nonce may have any number of bits between 8 and 2^64, but it MUST The nonce may have any number of bits between 8 and (2^64)-1, but it
be a multiple of 8 bits. Within the scope of any GMAC key, the nonce MUST be a multiple of 8 bits. Within the scope of any GMAC key, the
value MUST be unique. A nonce value of 12 octets can be processed nonce value MUST be unique. A nonce value of 12 octets can be
more efficiently, so that length for the nonce value is RECOMMENDED. processed more efficiently, so that length for the nonce value is
RECOMMENDED.
The GMACParameters length parameter field tells the size of the The GMACParameters length parameter field tells the size of the
message authentication code in octets. The length may have a value message authentication code in octets. GMAC supports lengths between
between 12 and 16, inclusive. A length of 12 octets is RECOMMENDED. 12 and 16 octets, inclusive. However, for use with CRMF, the maximum
length of 16 octets MUST be used.
4. IANA Considerations 5. IANA Considerations
This document makes no requests of the IANA. This document makes no requests of the IANA.
5. Security Considerations 6. Security Considerations
The security of the password-based MAC relies on the number of times The security of the password-based MAC relies on the number of times
the hash function is applied as well as the entropy of the shared the hash function is applied as well as the entropy of the shared
secret (the password). Hardware support for hash calculation is secret (the password). Hardware support for hash calculation is
available at very low cost [PHS], which reduces the protection available at very low cost [PHS], which reduces the protection
provided by a high iterationCount value. Therefore, the entropy of provided by a high iterationCount value. Therefore, the entropy of
the password is crucial for the security of password-based MAC the password is crucial for the security of the password-based MAC
function. In 2010, researchers showed that about half of the real- function. In 2010, researchers showed that about half of the real-
world passwords can be broken with less than 150 million trials, world passwords can be broken with less than 150 million trials,
indicating a median entropy of only 27 bits [DMR]. Higher entropy indicating a median entropy of only 27 bits [DMR]. Higher entropy
can be achieved by using randomly generated strings. For example, can be achieved by using randomly generated strings. For example,
assuming an alphabet of 60 characters a randomly chosen password with assuming an alphabet of 60 characters a randomly chosen password with
10 characters offers 59 bits a entropy, and 20 characters offers 118 10 characters offers 59 bits a entropy, and 20 characters offers 118
bits of entropy. Using a one-time password also increases the bits of entropy. Using a one-time password also increases the
security of the MAC, assuming that the integrity-protected security of the MAC, assuming that the integrity-protected
transaction will complete before the attacker is able to learn the transaction will complete before the attacker is able to learn the
password with an offline attack. password with an offline attack.
skipping to change at page 6, line 14 skipping to change at page 6, line 43
attacks will evolve, it is certain that they will get better. It is attacks will evolve, it is certain that they will get better. It is
unknown how much better they will become or when the advances will unknown how much better they will become or when the advances will
happen. For this reason, the algorithm requirements for CRMF are happen. For this reason, the algorithm requirements for CRMF are
updated by this specification. updated by this specification.
When a Password-Based MAC is used, implementations must protect the When a Password-Based MAC is used, implementations must protect the
password and the MAC key. Compromise of either the password or the password and the MAC key. Compromise of either the password or the
MAC key may result in the ability of an attacker to undermine MAC key may result in the ability of an attacker to undermine
authentication. authentication.
6. Acknowledgements 7. Acknowledgements
Many thanks to Hans Aschauer, Hendrik Brockhaus, Quynh Dang, Tomas Many thanks to Hans Aschauer, Hendrik Brockhaus, Quynh Dang, Roman
Gustavsson, Jonathan Hammell, Lijun Liao, Tim Polk, Mike StJohns, and Danyliw, Tomas Gustavsson, Jonathan Hammell, Lijun Liao, Mike
Sean Turner for their careful review and improvements. Ounsworth, Tim Polk, Mike StJohns, and Sean Turner for their careful
review and improvements.
7. References 8. References
7.1. Normative References 8.1. Normative References
[AES] "Advanced encryption standard (AES)", National Institute [AES] National Institute of Standards and Technology, "Advanced
of Standards and Technology report, encryption standard (AES)", DOI 10.6028/nist.fips.197,
DOI 10.6028/nist.fips.197, November 2001, November 2001, <https://doi.org/10.6028/nist.fips.197>.
<https://doi.org/10.6028/nist.fips.197>.
[GMAC] Dworkin, M., "Recommendation for block cipher modes of [GMAC] National Institute of Standards and Technology,
operation :: GaloisCounter Mode (GCM) and GMAC", National "Recommendation for block cipher modes of operation:
Institute of Standards and Technology report, Galois Counter Mode (GCM) and GMAC",
DOI 10.6028/nist.sp.800-38d, 2007, DOI 10.6028/nist.sp.800-38d, 2007,
<https://doi.org/10.6028/nist.sp.800-38d>. <https://doi.org/10.6028/nist.sp.800-38d>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC4211] Schaad, J., "Internet X.509 Public Key Infrastructure [RFC4211] Schaad, J., "Internet X.509 Public Key Infrastructure
Certificate Request Message Format (CRMF)", RFC 4211, Certificate Request Message Format (CRMF)", RFC 4211,
DOI 10.17487/RFC4211, September 2005, DOI 10.17487/RFC4211, September 2005,
<https://www.rfc-editor.org/info/rfc4211>. <https://www.rfc-editor.org/info/rfc4211>.
[RFC8018] Moriarty, K., Ed., Kaliski, B., and A. Rusch, "PKCS #5:
Password-Based Cryptography Specification Version 2.1",
RFC 8018, DOI 10.17487/RFC8018, January 2017,
<https://www.rfc-editor.org/info/rfc8018>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[SHS] Dang, Q., "Secure Hash Standard", National Institute of [SHS] National Institute of Standards and Technology, "Secure
Standards and Technology report, Hash Standard", DOI 10.6028/nist.fips.180-4, July 2015,
DOI 10.6028/nist.fips.180-4, July 2015,
<https://doi.org/10.6028/nist.fips.180-4>. <https://doi.org/10.6028/nist.fips.180-4>.
7.2. Informative References 8.2. Informative References
[DIGALM] National Institute of Standards and Technology, "Digital
identity guidelines: authentication and lifecycle
management", DOI 10.6028/nist.sp.800-63b, June 2017,
<https://doi.org/10.6028/nist.sp.800-63b>.
[DMR] Dell'Amico, M., Michiardi, P., and Y. Roudier, "Password [DMR] Dell'Amico, M., Michiardi, P., and Y. Roudier, "Password
Strength: An Empirical Analysis", 2010 Proceedings Strength: An Empirical Analysis",
IEEE INFOCOM, DOI 10.1109/infcom.2010.5461951, March 2010, DOI 10.1109/INFCOM.2010.5461951, March 2010,
<https://doi.org/10.1109/infcom.2010.5461951>. <https://doi.org/10.1109/INFCOM.2010.5461951>.
[I-D.housley-lamps-cms-aes-mac-alg] [I-D.ietf-lamps-cms-aes-gmac-alg]
Housley, R., "Using the AES-GMAC Algorithm with the Housley, R., "Using the AES-GMAC Algorithm with the
Cryptographic Message Syntax (CMS)", Work in Progress, Cryptographic Message Syntax (CMS)", Work in Progress,
Internet-Draft, draft-housley-lamps-cms-aes-mac-alg-00, 9 Internet-Draft, draft-ietf-lamps-cms-aes-gmac-alg-03,
November 2020, <http://www.ietf.org/internet-drafts/draft- 27 January 2020, <http://www.ietf.org/internet-drafts/
housley-lamps-cms-aes-mac-alg-00.txt>. draft-ietf-lamps-cms-aes-gmac-alg-02.txt>.
[NISTSP800-63B]
Grassi, P., Fenton, J., Newton, E., Perlner, R.,
Regenscheid, A., Burr, W., Richer, J., Lefkovitz, N.,
Danker, J., Choong, Y., Greene, K., and M. Theofanos,
"Digital identity guidelines: authentication and lifecycle
management", National Institute of Standards and
Technology report, DOI 10.6028/nist.sp.800-63b, June 2017,
<https://doi.org/10.6028/nist.sp.800-63b>.
[PHS] Pathirana, A., Halgamuge, M., and A. Syed, "Energy [PHS] Pathirana, A., Halgamuge, M., and A. Syed, "Energy
efficient bitcoin mining to maximize the mining profit: efficient bitcoin mining to maximize the mining profit:
Using data from 119 bitcoin mining hardware setups", Using data from 119 bitcoin mining hardware setups",
International Conference on Advances in Business International Conference on Advances in Business
Management and Information Technology, pp 1-14, November Management and Information Technology, pp 1-14, November
2019. 2019.
[RFC4231] Nystrom, M., "Identifiers and Test Vectors for HMAC-SHA- [RFC4231] Nystrom, M., "Identifiers and Test Vectors for HMAC-SHA-
224, HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512", 224, HMAC-SHA-256, HMAC-SHA-384, and HMAC-SHA-512",
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