Cryptographic Message Syntax (CMS)
RFC 5652

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Network Working Group                                         R. Housley
Request for Comments: 5652                                Vigil Security
Obsoletes: 3852                                           September 2009
Category: Standards Track

                   Cryptographic Message Syntax (CMS)

Abstract

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

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 and License Notice

   Copyright (c) 2009 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
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   Contributions published or made publicly available before November
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   the copyright in such materials, this document may not be modified
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   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Housley                     Standards Track                     [Page 1]
RFC 5652              Cryptographic Message Syntax        September 2009

Table of Contents

   1. Introduction ....................................................3
      1.1. Evolution of the CMS .......................................4
           1.1.1. Changes Since PKCS #7 Version 1.5 ...................4
           1.1.2. Changes Since RFC 2630 ..............................4
           1.1.3. Changes Since RFC 3369 ..............................5
           1.1.4. Changes Since RFC 3852 ..............................5
      1.2. Terminology ................................................5
      1.3. Version Numbers ............................................6
   2. General Overview ................................................6
   3. General Syntax ..................................................7
   4. Data Content Type ...............................................7
   5. Signed-data Content Type ........................................8
      5.1. SignedData Type ............................................9
      5.2. EncapsulatedContentInfo Type ..............................11
           5.2.1. Compatibility with PKCS #7 .........................12
      5.3. SignerInfo Type ...........................................13
      5.4. Message Digest Calculation Process ........................16
      5.5. Signature Generation Process ..............................16
      5.6. Signature Verification Process ............................17
   6. Enveloped-Data Content Type ....................................17
      6.1. EnvelopedData Type ........................................18
      6.2. RecipientInfo Type ........................................21
           6.2.1. KeyTransRecipientInfo Type .........................22
           6.2.2. KeyAgreeRecipientInfo Type .........................23
           6.2.3. KEKRecipientInfo Type ..............................25
           6.2.4. PasswordRecipientInfo Type .........................26
           6.2.5. OtherRecipientInfo Type ............................27
      6.3. Content-encryption Process ................................27
      6.4. Key-Encryption Process ....................................28
   7. Digested-Data Content Type .....................................28
   8. Encrypted-Data Content Type ....................................29
   9. Authenticated-Data Content Type ................................30
      9.1. AuthenticatedData Type ....................................31
      9.2. MAC Generation ............................................33
      9.3. MAC Verification ..........................................34