CBOR Object Signing and Encryption (COSE): Structures and Process
draft-ietf-cose-rfc8152bis-struct-03

Document Type Active Internet-Draft (cose WG)
Last updated 2019-06-10
Replaces draft-schaad-cose-rfc8152bis-struct
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COSE Working Group                                             J. Schaad
Internet-Draft                                            August Cellars
Obsoletes: 8152 (if approved)                              June 10, 2019
Intended status: Standards Track
Expires: December 12, 2019

   CBOR Object Signing and Encryption (COSE): Structures and Process
                  draft-ietf-cose-rfc8152bis-struct-03

Abstract

   Concise Binary Object Representation (CBOR) is a data format designed
   for small code size and small message size.  There is a need for the
   ability to have basic security services defined for this data format.
   This document defines the CBOR Object Signing and Encryption (COSE)
   protocol.  This specification describes how to create and process
   signatures, message authentication codes, and encryption using CBOR
   for serialization.  This specification additionally describes how to
   represent cryptographic keys using CBOR.

   This document along with [I-D.ietf-cose-rfc8152bis-algs] obsoletes
   RFC8152.

Contributing to this document

   The source for this draft is being maintained in GitHub.  Suggested
   changes should be submitted as pull requests at <https://github.com/
   cose-wg/cose-rfc8152bis>.  Instructions are on that page as well.
   Editorial changes can be managed in GitHub, but any substantial
   issues need to be discussed on the COSE mailing list.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on December 12, 2019.

Schaad                  Expires December 12, 2019               [Page 1]
Internet-Draft               COSE Structure                    June 2019

Copyright Notice

   Copyright (c) 2019 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
   (https://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
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   include Simplified BSD License text as described in Section 4.e of
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.1.  Design Changes from JOSE  . . . . . . . . . . . . . . . .   5
     1.2.  Changes from RFC8152  . . . . . . . . . . . . . . . . . .   6
     1.3.  Requirements Terminology  . . . . . . . . . . . . . . . .   6
     1.4.  CBOR Grammar  . . . . . . . . . . . . . . . . . . . . . .   6
     1.5.  CBOR-Related Terminology  . . . . . . . . . . . . . . . .   7
     1.6.  Document Terminology  . . . . . . . . . . . . . . . . . .   8
   2.  Basic COSE Structure  . . . . . . . . . . . . . . . . . . . .   8
   3.  Header Parameters . . . . . . . . . . . . . . . . . . . . . .  11
     3.1.  Common COSE Headers Parameters  . . . . . . . . . . . . .  13
   4.  Signing Objects . . . . . . . . . . . . . . . . . . . . . . .  17
     4.1.  Signing with One or More Signers  . . . . . . . . . . . .  17
     4.2.  Signing with One Signer . . . . . . . . . . . . . . . . .  19
     4.3.  Externally Supplied Data  . . . . . . . . . . . . . . . .  20
     4.4.  Signing and Verification Process  . . . . . . . . . . . .  21
   5.  Counter Signatures  . . . . . . . . . . . . . . . . . . . . .  22
     5.1.  Full Countersignatures  . . . . . . . . . . . . . . . . .  23
     5.2.  Abbreviated Countersignatures . . . . . . . . . . . . . .  24
   6.  Encryption Objects  . . . . . . . . . . . . . . . . . . . . .  24
     6.1.  Enveloped COSE Structure  . . . . . . . . . . . . . . . .  25
       6.1.1.  Content Key Distribution Methods  . . . . . . . . . .  26
     6.2.  Single Recipient Encrypted  . . . . . . . . . . . . . . .  27
     6.3.  How to Encrypt and Decrypt for AEAD Algorithms  . . . . .  28
     6.4.  How to Encrypt and Decrypt for AE Algorithms  . . . . . .  30
   7.  MAC Objects . . . . . . . . . . . . . . . . . . . . . . . . .  31
     7.1.  MACed Message with Recipients . . . . . . . . . . . . . .  32
     7.2.  MACed Messages with Implicit Key  . . . . . . . . . . . .  33
     7.3.  How to Compute and Verify a MAC . . . . . . . . . . . . .  34
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