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RFC 9338

Internet Engineering Task Force (IETF) J. Schaad Request for Comments: 9338 August Cellars STD: 96 December 2022 Updates: 9052 Category: Standards Track ISSN: 2070-1721

  CBOR Object Signing and Encryption (COSE): Countersignatures

Abstract

Concise Binary Object Representation (CBOR) is a data format designed for small code size and small message size. CBOR Object Signing and Encryption (COSE) defines a set of security services for CBOR. This document defines a countersignature algorithm along with the needed header parameters and CBOR tags for COSE. This document updates RFC 9052.

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 7841.

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc9338.

Copyright Notice

Copyright (c) 2022 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 to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.

Table of Contents

  1. Introduction 1.1. Requirements Terminology 1.2. CBOR Grammar 1.3. Document Terminology
  2. Countersignature Header Parameters
  3. Version 2 Countersignatures 3.1. Full Countersignatures 3.2. Abbreviated Countersignatures 3.3. Signing and Verification Process
  4. CBOR Encoding Restrictions
  5. IANA Considerations 5.1. CBOR Tags Registry 5.2. COSE Header Parameters Registry
  6. Security Considerations
  7. References 7.1. Normative References 7.2. Informative References Appendix A. Examples A.1. Examples of Signed Messages A.1.1. Countersignature A.2. Examples of Signed1 Messages A.2.1. Countersignature A.3. Examples of Enveloped Messages A.3.1. Countersignature on Encrypted Content A.4. Examples of Encrypted Messages A.4.1. Countersignature on Encrypted Content A.5. Examples of MACed Messages A.5.1. Countersignature on MAC Content A.6. Examples of MAC0 Messages A.6.1. Countersignature on MAC0 Content Acknowledgments Author's Address

Acknowledgments

This document is a product of the COSE Working Group of the IETF.

The initial draft version of the specification was based to some degree on the outputs of the JOSE and S/MIME Working Groups.

Jim Schaad passed on 3 October 2020. This document is primarily his work. Russ Housley served as the document editor after Jim's untimely death, mostly helping with the approval and publication processes. Jim deserves all credit for the technical content.

Jim Schaad and Jonathan Hammell provided the examples in Appendix A.

The reviews by Carsten Bormann, Ben Kaduk, and Elwyn Davies greatly improved the clarity of the document.

Author's Address

Jim Schaad August Cellars United States of America

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