--- 1/draft-ietf-lamps-crmf-update-algs-06.txt 2021-04-08 08:13:35.870918015 -0700 +++ 2/draft-ietf-lamps-crmf-update-algs-07.txt 2021-04-08 08:13:35.898918713 -0700 @@ -1,20 +1,20 @@ Network Working Group R. Housley Internet-Draft Vigil Security -Updates: 4211 (if approved) 6 April 2021 +Updates: 4211 (if approved) 8 April 2021 Intended status: Standards Track -Expires: 8 October 2021 +Expires: 10 October 2021 Algorithm Requirements Update to the Internet X.509 Public Key Infrastructure Certificate Request Message Format (CRMF) - draft-ietf-lamps-crmf-update-algs-06 + draft-ietf-lamps-crmf-update-algs-07 Abstract This document updates the cryptographic algorithm requirements for the Password-Based Message Authentication Code in the Internet X.509 Public Key Infrastructure Certificate Request Message Format (CRMF) specified in RFC 4211. Status of This Memo @@ -24,21 +24,21 @@ 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 8 October 2021. + This Internet-Draft will expire on 10 October 2021. Copyright Notice Copyright (c) 2021 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 @@ -117,21 +117,21 @@ 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 [RFC4211]. Implementations MAY also support PBMAC1 - presented in Section 7.1 of [RFC8018]. + as 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 on a one-way function to compute a symmetric key from the password and a MAC algorithm. This section specifies algorithm requirements for the one-way function and the MAC algorithm. 4.1. Introduction Paragraph @@ -207,35 +207,35 @@ mac identifies the algorithm and associated parameters of the MAC function to be used. All implementations MUST support HMAC-SHA1 [HMAC]. All implementations SHOULD support DES-MAC and Triple- DES-MAC [PKCS11]. NEW: mac identifies the algorithm and associated parameters of the MAC function to be used. All implementations MUST support HMAC-SHA256 - [HMAC]. All implementations SHOULD support AES-GMAC AES [GMAC] - with a 128 bit key. + [HMAC]. All implementations SHOULD support AES-GMAC [AES][GMAC] + with a 128-bit key. For convenience, the identifiers for these two algorithms are repeated here. The ASN.1 algorithm identifier for HMAC-SHA256 is defined in [RFC4231]: id-hmacWithSHA256 OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) digestAlgorithm(2) 9 } When this object identifier is used in the ASN.1 algorithm identifier, the parameters SHOULD be present. When present, the - parameters MUST contain a type of NULL. + parameters MUST contain a type of NULL as specified in [RFC4231]. The ASN.1 algorithm identifier for AES-GMAC [AES][GMAC] with a 128-bit key is defined in [I-D.ietf-lamps-cms-aes-gmac-alg]: id-aes128-GMAC OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840) organization(1) gov(101) csor(3) nistAlgorithm(4) aes(1) 9 } When this object identifier is used in the ASN.1 algorithm identifier, the parameters MUST be present, and the parameters MUST @@ -265,29 +265,29 @@ 6. Security Considerations 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 secret (the password). Hardware support for hash calculation is available at very low cost [PHS], which reduces the protection provided by a high iterationCount value. Therefore, the entropy of the password is crucial for the security of the password-based MAC function. In 2010, researchers showed that about half of the real- - world passwords can be broken with less than 150 million trials, - indicating a median entropy of only 27 bits [DMR]. Higher entropy - can be achieved by using randomly generated strings. For example, - assuming an alphabet of 60 characters a randomly chosen password with - 10 characters offers 59 bits of entropy, and 20 characters offers 118 - bits of entropy. Using a one-time password also increases the - security of the MAC, assuming that the integrity-protected - transaction will complete before the attacker is able to learn the - password with an offline attack. + world passwords in a leaked corpus can be broken with less than 150 + million trials, indicating a median entropy of only 27 bits [DMR]. + Higher entropy can be achieved by using randomly generated strings. + For example, assuming an alphabet of 60 characters a randomly chosen + password with 10 characters offers 59 bits of entropy, and 20 + characters offers 118 bits of entropy. Using a one-time password + also increases the security of the MAC, assuming that the integrity- + protected transaction will complete before the attacker is able to + learn the password with an offline attack. Please see [RFC8018] for security considerations related to PBMAC1. Please see [HMAC] and [SHS] for security considerations related to HMAC-SHA256. Please see [AES] and [GMAC] for security considerations related to AES-GMAC. Cryptographic algorithms age; they become weaker with time. As new @@ -302,43 +302,50 @@ When a Password-Based MAC is used, implementations must protect 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 authentication. 7. Acknowledgements Many thanks to Hans Aschauer, Hendrik Brockhaus, Quynh Dang, Roman Danyliw, Lars Eggert, Tomas Gustavsson, Jonathan Hammell, Tim - Hollebeek, Erik Kline, Lijun Liao, Mike Ounsworth, Francesca - Palombini, Tim Polk, Ines Robles, Mike StJohns, and Sean Turner for - their careful review and improvements. + Hollebeek, Ben Kaduk, Erik Kline, Lijun Liao, Mike Ounsworth, + Francesca Palombini, Tim Polk, Ines Robles, Mike StJohns, and Sean + Turner for their careful review and improvements. 8. References 8.1. Normative References [AES] National Institute of Standards and Technology, "Advanced encryption standard (AES)", DOI 10.6028/nist.fips.197, November 2001, . [GMAC] National Institute of Standards and Technology, "Recommendation for block cipher modes of operation: Galois Counter Mode (GCM) and GMAC", DOI 10.6028/nist.sp.800-38d, 2007, . [HMAC] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed- Hashing for Message Authentication", RFC 2104, DOI 10.17487/RFC2104, February 1997, . + [I-D.ietf-lamps-cms-aes-gmac-alg] + Housley, R., "Using the AES-GMAC Algorithm with the + Cryptographic Message Syntax (CMS)", Work in Progress, + Internet-Draft, draft-ietf-lamps-cms-aes-gmac-alg-02, 30 + December 2020, . + [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC4211] Schaad, J., "Internet X.509 Public Key Infrastructure Certificate Request Message Format (CRMF)", RFC 4211, DOI 10.17487/RFC4211, September 2005, . @@ -364,27 +371,20 @@ [DIGALM] National Institute of Standards and Technology, "Digital identity guidelines: authentication and lifecycle management", DOI 10.6028/nist.sp.800-63b, June 2017, . [DMR] Dell'Amico, M., Michiardi, P., and Y. Roudier, "Password Strength: An Empirical Analysis", DOI 10.1109/INFCOM.2010.5461951, March 2010, . - [I-D.ietf-lamps-cms-aes-gmac-alg] - Housley, R., "Using the AES-GMAC Algorithm with the - Cryptographic Message Syntax (CMS)", Work in Progress, - Internet-Draft, draft-ietf-lamps-cms-aes-gmac-alg-02, 30 - December 2020, . - [PHS] Pathirana, A., Halgamuge, M., and A. Syed, "Energy efficient bitcoin mining to maximize the mining profit: Using data from 119 bitcoin mining hardware setups", International Conference on Advances in Business Management and Information Technology, pp 1-14, November 2019. [PKCS11] RSA Laboratories, "The Public-Key Cryptography Standards - PKCS #11 v2.11: Cryptographic Token Interface Standard", June 2001.