RFC 3852 (rfc3852) - Page 1 of 56


Cryptographic Message Syntax (CMS)



Alternative Format: Original Text Document



Network Working Group                                         R. Housley
Request for Comments: 3852                                Vigil Security
Obsoletes: 3369                                                July 2004
Category: Standards Track


                   Cryptographic Message Syntax (CMS)

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2004).

Abstract

   This document describes the Cryptographic Message Syntax (CMS).  This
   syntax is used to digitally sign, digest, authenticate, or encrypt
   arbitrary message content.

Table of Contents

   1.   Introduction. . . . . . . . . . . . . . . . . . . . . . . . .  3
        1.1.   Evolution of the CMS . . . . . . . . . . . . . . . . .  3
               1.1.1.  Changes Since PKCS #7 Version 1.5. . . . . . .  3
               1.1.2.  Changes Since RFC 2630 . . . . . . . . . . . .  4
               1.1.3.  Changes Since RFC 3369 . . . . . . . . . . . .  4
        1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . .  5
        1.3.  Version Numbers . . . . . . . . . . . . . . . . . . . .  5
   2.   General Overview. . . . . . . . . . . . . . . . . . . . . . .  5
   3.   General Syntax  . . . . . . . . . . . . . . . . . . . . . . .  6
   4.   Data Content Type . . . . . . . . . . . . . . . . . . . . . .  6
   5.   Signed-data Content Type. . . . . . . . . . . . . . . . . . .  7
        5.1.   SignedData Type. . . . . . . . . . . . . . . . . . . .  8
        5.2.   EncapsulatedContentInfo Type . . . . . . . . . . . . . 10
               5.2.1.   Compatibility with PKCS #7. . . . . . . . . . 11
        5.3.   SignerInfo Type. . . . . . . . . . . . . . . . . . . . 12
        5.4.   Message Digest Calculation Process . . . . . . . . . . 14
        5.5.   Signature Generation Process . . . . . . . . . . . . . 15
        5.6.   Signature Verification Process . . . . . . . . . . . . 15
   6.   Enveloped-data Content Type . . . . . . . . . . . . . . . . . 16
        6.1.   EnvelopedData Type . . . . . . . . . . . . . . . . . . 17



Housley                     Standards Track