Algorithms for Cryptographic Message Syntax (CMS) Key Package Receipt and Error Content Types
RFC 7192

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 00
• 01
• 02
• 03
• 04

Internet Engineering Task Force (IETF)                         S. Turner
Request for Comments: 7192                                          IECA
Category: Standards Track                                     April 2014
ISSN: 2070-1721

           Algorithms for Cryptographic Message Syntax (CMS)
              Key Package Receipt and Error Content Types

Abstract

   This document describes the conventions for using several
   cryptographic algorithms with the Cryptographic Message Syntax (CMS)
   key package receipt and error content types.  Specifically, it
   includes conventions necessary to implement SignedData,
   EnvelopedData, EncryptedData, and AuthEnvelopedData.

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/rfc7192.

Copyright Notice

   Copyright (c) 2014 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.

Turner                       Standards Track                    [Page 1]
RFC 7192       Algs for CMS Key Package Rcpt Content Type     April 2014

1.  Introduction

   This document describes the conventions for using several
   cryptographic algorithms with the Cryptographic Message Syntax (CMS)
   key package receipt and error content types [RFC7191].  Specifically,
   it includes conventions necessary to implement SignedData [RFC5652],
   EnvelopedData [RFC5652], EncryptedData [RFC5652], and
   AuthEnvelopedData [RFC5083].

   This document does not define any new algorithms; instead, it refers
   to previously defined algorithms.  In fact, the algorithm
   requirements in this document are the same as those in [RFC5959],
   [RFC6033], [RFC6160], [RFC6161], and [RFC6162] with the following
   exceptions: the content-encryption algorithm is AES in Cipher Block
   Chaining (CBC) mode as opposed to AES Key Wrap with Message Length
   Indicator (MLI) and the key-wrap algorithm is AES Key Wrap as opposed
   to AES Key Wrap with MLI.  The rationale for the difference is that
   the receipt and error content types are not keys; therefore, AES Key
   Wrap with MLI is not appropriate for the content-encryption
   algorithm.  If an implementation is not using AES Key Wrap with MLI
   as the content-encryption algorithm, then there's no need to keep the
   key-wrap algorithm the same as the content encryption algorithm.

   NOTE: [RFC7191] only requires that the key package receipt be signed.

1.1.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   [RFC2119].

2.  SignedData

   If an implementation supports SignedData, then it MUST support the
   signature scheme RSA [RFC3370] and SHOULD support the signature
   schemes RSA Probabilistic Signature Scheme (RSASSA-PSS) [RFC4056] and
   Digital Signature Algorithm (DSA) [RFC3370].  Additionally,
   implementations MUST support the hash function SHA-256 [RFC5754] in
   concert with these signature schemes, and they SHOULD support the
   hash function SHA-1 [RFC3370].  Implementations can also choose the
   to support Elliptic Curve Digital Signature Algorithm (ECDSA)
   [RFC5753] and [RFC6090].

Turner                       Standards Track                    [Page 2]
RFC 7192       Algs for CMS Key Package Rcpt Content Type     April 2014

3.  EnvelopedData

   If an implementation supports EnvelopedData, then it MUST implement
   key transport and it MAY implement key agreement.

   When key transport is used, RSA encryption [RFC3370] MUST be
   supported, and RSA Encryption Scheme - Optimal Asymmetric Encryption
   Padding (RSAES-OAEP) [RFC3560] SHOULD be supported.

   When key agreement is used, Diffie-Hellman (DH) ephemeral-static
   [RFC3370] MUST be supported.  When key agreement is used, Elliptic
   Curve Diffie-Hellman (ECDH) [RFC5753] [RFC6090] MAY be supported.