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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group A. Melnikov, Ed. 3 Internet-Draft Isode Ltd 4 Intended status: Standards Track May 14, 2020 5 Expires: November 15, 2020 7 SCRAM-SHA-512 and SCRAM-SHA-512-PLUS Simple Authentication and Security 8 Layer (SASL) Mechanisms 9 draft-melnikov-scram-sha-512-00 11 Abstract 13 This document registers the Simple Authentication and Security Layer 14 (SASL) mechanisms SCRAM-SHA-512 and SCRAM-SHA-512-PLUS. 16 Status of This Memo 18 This Internet-Draft is submitted in full conformance with the 19 provisions of BCP 78 and BCP 79. 21 Internet-Drafts are working documents of the Internet Engineering 22 Task Force (IETF). Note that other groups may also distribute 23 working documents as Internet-Drafts. The list of current Internet- 24 Drafts is at https://datatracker.ietf.org/drafts/current/. 26 Internet-Drafts are draft documents valid for a maximum of six months 27 and may be updated, replaced, or obsoleted by other documents at any 28 time. It is inappropriate to use Internet-Drafts as reference 29 material or to cite them other than as "work in progress." 31 This Internet-Draft will expire on November 15, 2020. 33 Copyright Notice 35 Copyright (c) 2020 IETF Trust and the persons identified as the 36 document authors. All rights reserved. 38 This document is subject to BCP 78 and the IETF Trust's Legal 39 Provisions Relating to IETF Documents 40 (https://trustee.ietf.org/license-info) in effect on the date of 41 publication of this document. Please review these documents 42 carefully, as they describe your rights and restrictions with respect 43 to this document. Code Components extracted from this document must 44 include Simplified BSD License text as described in Section 4.e of 45 the Trust Legal Provisions and are provided without warranty as 46 described in the Simplified BSD License. 48 Table of Contents 50 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 51 2. Key Word Definitions . . . . . . . . . . . . . . . . . . . . 2 52 3. SCRAM-SHA-512 and SCRAM-SHA-512-PLUS . . . . . . . . . . . . 2 53 4. Security Considerations . . . . . . . . . . . . . . . . . . . 3 54 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 55 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 56 6.1. Normative References . . . . . . . . . . . . . . . . . . 4 57 6.2. Informative References . . . . . . . . . . . . . . . . . 5 58 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 6 59 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6 61 1. Introduction 63 This document registers the SASL [RFC4422] mechanisms SCRAM-SHA-512 64 and SCRAM-SHA-512-PLUS. SHA-512 has stronger security properties 65 than SHA-1, and it is expected that SCRAM mechanisms based on it will 66 have greater predicted longevity than the SCRAM mechanisms based on 67 SHA-1. 69 2. Key Word Definitions 71 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 72 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 73 "OPTIONAL" in this document are to be interpreted as described in BCP 74 14 [RFC2119] [RFC8174] when, and only when, they appear in all 76 3. SCRAM-SHA-512 and SCRAM-SHA-512-PLUS 78 The SCRAM-SHA-512 and SCRAM-SHA-512-PLUS SASL mechanisms are defined 79 in the same way that SCRAM-SHA-1 and SCRAM-SHA-1-PLUS are defined in 80 [RFC5802], except that the hash function for HMAC() and H() uses 81 SHA-512 instead of SHA-1 [RFC6234]. 83 For the SCRAM-SHA-512 and SCRAM-SHA-512-PLUS SASL mechanisms, the 84 hash iteration-count announced by a server SHOULD be at least 4096. 86 The GSS-API mechanism OID for SCRAM-SHA-512 is 1.3.6.1.5.5. (see 87 Section 5). 89 This is a simple example of a SCRAM-SHA-512 authentication exchange 90 when the client doesn't support channel bindings. The username 91 'user' and password 'pencil' are being used. 93 4. Security Considerations 95 The security considerations from [RFC5802] still apply. 97 To be secure, either SCRAM-SHA-512-PLUS and SCRAM-SHA-1-PLUS MUST be 98 used over a TLS channel that has had the session hash extension 99 [RFC7627] negotiated, or session resumption MUST NOT have been used. 101 See [RFC4270] and [RFC6194] for reasons to move from SHA-1 to a 102 strong security mechanism like SHA-512. 104 The strength of this mechanism is dependent in part on the hash 105 iteration-count, as denoted by "i" in [RFC5802]. As a rule of thumb, 106 the hash iteration-count should be such that a modern machine will 107 take 0.1 seconds to perform the complete algorithm; however, this is 108 unlikely to be practical on mobile devices and other relatively low- 109 performance systems. At the time this was written, the rule of thumb 110 gives around 15,000 iterations required; however, a hash iteration- 111 count of 4096 takes around 0.5 seconds on current mobile handsets. 112 This computational cost can be avoided by caching the ClientKey 113 (assuming the Salt and hash iteration-count is stable). Therefore, 114 the recommendation of this specification is that the hash iteration- 115 count SHOULD be at least 4096, but careful consideration ought to be 116 given to using a significantly higher value, particularly where 117 mobile use is less important. 119 5. IANA Considerations 121 IANA is requested to add the following new SASL SCRAM mechanisms to 122 the "SASL SCRAM Family Mechanisms" registry: 124 To: iana@iana.org 126 Subject: Registration of a new SASL SCRAM Family mechanism SCRAM- 127 SHA-512 129 SASL mechanism name (or prefix for the family): SCRAM-SHA-512 131 Security considerations: Section 4 of RFC XXXX 133 Published specification (optional, recommended): RFC XXXX 135 Minimum iteration-count: 4096 137 OID: 1.3.6.1.5.5. 138 Person & email address to contact for further information: IETF 139 KITTEN WG 141 Intended usage: COMMON 143 Owner/Change controller: IESG 145 Note: 147 To: iana@iana.org 149 Subject: Registration of a new SASL SCRAM Family mechanism SCRAM- 150 SHA-512-PLUS 152 SASL mechanism name (or prefix for the family): SCRAM-SHA- 153 512-PLUS 155 Security considerations: Section 4 of RFC XXXX 157 Published specification (optional, recommended): RFC XXXX 159 Minimum iteration-count: 4096 161 OID: 1.3.6.1.5.5. 163 Person & email address to contact for further information: IETF 164 KITTEN WG 166 Intended usage: COMMON 168 Owner/Change controller: IESG 170 Note: 172 6. References 174 6.1. Normative References 176 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 177 Requirement Levels", BCP 14, RFC 2119, 178 DOI 10.17487/RFC2119, March 1997, 179 . 181 [RFC4422] Melnikov, A., Ed. and K. Zeilenga, Ed., "Simple 182 Authentication and Security Layer (SASL)", RFC 4422, 183 DOI 10.17487/RFC4422, June 2006, 184 . 186 [RFC5802] Newman, C., Menon-Sen, A., Melnikov, A., and N. Williams, 187 "Salted Challenge Response Authentication Mechanism 188 (SCRAM) SASL and GSS-API Mechanisms", RFC 5802, 189 DOI 10.17487/RFC5802, July 2010, 190 . 192 [RFC6234] Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms 193 (SHA and SHA-based HMAC and HKDF)", RFC 6234, 194 DOI 10.17487/RFC6234, May 2011, 195 . 197 [RFC7627] Bhargavan, K., Ed., Delignat-Lavaud, A., Pironti, A., 198 Langley, A., and M. Ray, "Transport Layer Security (TLS) 199 Session Hash and Extended Master Secret Extension", 200 RFC 7627, DOI 10.17487/RFC7627, September 2015, 201 . 203 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 204 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 205 May 2017, . 207 6.2. Informative References 209 [RFC4270] Hoffman, P. and B. Schneier, "Attacks on Cryptographic 210 Hashes in Internet Protocols", RFC 4270, 211 DOI 10.17487/RFC4270, November 2005, 212 . 214 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 215 IANA Considerations Section in RFCs", RFC 5226, 216 DOI 10.17487/RFC5226, May 2008, 217 . 219 [RFC6194] Polk, T., Chen, L., Turner, S., and P. Hoffman, "Security 220 Considerations for the SHA-0 and SHA-1 Message-Digest 221 Algorithms", RFC 6194, DOI 10.17487/RFC6194, March 2011, 222 . 224 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 225 (TLS) Protocol Version 1.2", RFC 5246, 226 DOI 10.17487/RFC5246, August 2008, 227 . 229 Acknowledgements 231 This document is based on RFC 7677 by Tony Hansen. 233 Author's Address 235 Alexey Melnikov (editor) 236 Isode Ltd 237 14 Castle Mews 238 Hampton, Middlesex TW12 2NP 239 UK 241 EMail: alexey.melnikov@isode.com