Using Message Authentication Code (MAC) Encryption in the Cryptographic Message Syntax (CMS)
RFC 6476
Document | Type |
RFC - Proposed Standard
(January 2012; Errata)
Was draft-gutmann-cms-hmac-enc (individual in sec area)
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Author | Peter Gutmann | ||
Last updated | 2015-10-14 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Reviews | |||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 6476 (Proposed Standard) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Sean Turner | ||
IESG note | Peter Gutmann (pgut001@cs.auckland.ac.nz) is the Document Shepherd. | ||
Send notices to | (None) |
Internet Engineering Task Force (IETF) P. Gutmann Request for Comments: 6476 University of Auckland Category: Standards Track January 2012 ISSN: 2070-1721 Using Message Authentication Code (MAC) Encryption in the Cryptographic Message Syntax (CMS) Abstract This document specifies the conventions for using Message Authentication Code (MAC) encryption with the Cryptographic Message Syntax (CMS) authenticated-enveloped-data content type. This mirrors the use of a MAC combined with an encryption algorithm that's already employed in IPsec, Secure Socket Layer / Transport Layer Security (SSL/TLS) and Secure SHell (SSH), which is widely supported in existing crypto libraries and hardware and has been extensively analysed by the crypto community. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc6476. Copyright Notice Copyright (c) 2012 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 (http://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. Gutmann Standards Track [Page 1] RFC 6476 MAC Encryption in CMS January 2012 Table of Contents 1. Introduction ....................................................2 1.1. Conventions Used in This Document ..........................2 2. Background ......................................................2 3. CMS Encrypt-and-Authenticate Overview ...........................3 3.1. Rationale ..................................................3 4. CMS Encrypt-and-Authenticate ....................................4 4.1. Encrypt-and-Authenticate Message Processing ................5 4.2. Rationale ..................................................6 4.3. Test Vectors ...............................................8 5. SMIMECapabilities Attribute ....................................12 6. Security Considerations ........................................12 7. IANA Considerations ............................................13 8. Acknowledgements ...............................................14 9. References .....................................................14 9.1. Normative References ......................................14 9.2. Informative References ....................................14 1. Introduction This document specifies the conventions for using MAC-authenticated encryption with the Cryptographic Message Syntax (CMS) authenticated- enveloped-data content type. This mirrors the use of a MAC combined with an encryption algorithm that's already employed in IPsec, SSL/ TLS and SSH, which is widely supported in existing crypto libraries and hardware and has been extensively analysed by the crypto community. 1.1. Conventions Used in This Document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 2. Background Integrity-protected encryption is a standard feature of session- oriented security protocols like [IPsec], [SSH], and [TLS]. Until recently, however, integrity-protected encryption wasn't available for message-based security protocols like CMS, although [OpenPGP] added a form of integrity protection by encrypting a SHA-1 hash of the message alongside the message contents to provide authenticate- and-encrypt protection. Usability studies have shown that users expect encryption to provide integrity protection [Garfinkel], creating cognitive dissonance problems when the security mechanisms don't in fact provide this assurance. Gutmann Standards Track [Page 2] RFC 6476 MAC Encryption in CMS January 2012Show full document text