Internet Engineering Task Force (IETF) S. Turner
Request for Comments: 6162 IECA
Updates: 5959 April 2011
Category: Standards Track
Elliptic Curve Algorithms for Cryptographic Message Syntax (CMS)
Asymmetric Key Package Content Type
This document describes conventions for using Elliptic Curve
cryptographic algorithms with SignedData and EnvelopedData to protect
the AsymmetricKeyPackage content type. Specifically, it includes
conventions necessary to implement Elliptic Curve Diffie-Hellman
(ECDH) with EnvelopedData and Elliptic Curve Digital Signature
Algorithm (ECDSA) with SignedData. This document extends RFC 5959.
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
Copyright (c) 2011 IETF Trust and the persons identified as the
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[RFC5959] describes conventions necessary to protect the
AsymmetricKeyPackage content type [RFC5958] with Cryptographic
Message Syntax (CMS) protecting the following content types:
SignedData [RFC5652], EnvelopedData [RFC5652], EncryptedData
[RFC5652], AuthenticatedData [RFC5652], and AuthEnvelopedData
[RFC5083]. This document amends [RFC5959] by extending the
algorithms used with SignedData and EnvelopedData to include Elliptic
Curve Digital Signature Algorithm (ECDSA) and Elliptic Curve Diffie-
Hellman (ECDH), respectively. Familiarity with [RFC5959] and
[RFC5753] is assumed.
This document does not define any new algorithms; instead, it refers
to previously defined algorithms.
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
As noted in Asymmetric Key Packages [RFC5958], CMS can be used to
protect the AsymmetricKeyPackage. The following provides guidance
for SignedData [RFC5652] and EnvelopedData [RFC5652] when used with
Elliptic Curve algorithms.
If an implementation supports SignedData, then it MAY support ECDSA
When key agreement is used, standard (as opposed to cofactor) ECDH
[RFC6090][RFC5753] MAY be supported.
3. Public Key Sizes
The easiest way to implement SignedData and EnvelopedData is with
public key certificates [RFC5280][RFC5480]. If an implementation
supports ECDSA or ECDH, then it MUST support keys on the P-256 curve.