CBOR Object Signing and Encryption (COSE): Structures and Process
draft-ietf-cose-rfc8152bis-struct-08
COSE Working Group J. Schaad
Internet-Draft August Cellars
Obsoletes: 8152 (if approved) 9 March 2020
Intended status: Standards Track
Expires: 10 September 2020
CBOR Object Signing and Encryption (COSE): Structures and Process
draft-ietf-cose-rfc8152bis-struct-08
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
This note is to be removed before publishing as an RFC.
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."
Schaad Expires 10 September 2020 [Page 1]
Internet-Draft COSE Structure March 2020
This Internet-Draft will expire on 10 September 2020.
Copyright Notice
Copyright (c) 2020 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Requirements Terminology . . . . . . . . . . . . . . . . 5
1.2. Changes from RFC8152 . . . . . . . . . . . . . . . . . . 5
1.3. Design Changes from JOSE . . . . . . . . . . . . . . . . 6
1.4. CBOR Grammar . . . . . . . . . . . . . . . . . . . . . . 6
1.5. CBOR-Related Terminology . . . . . . . . . . . . . . . . 8
1.6. Document Terminology . . . . . . . . . . . . . . . . . . 8
2. Basic COSE Structure . . . . . . . . . . . . . . . . . . . . 9
3. Header Parameters . . . . . . . . . . . . . . . . . . . . . . 13
3.1. Common COSE Header Parameters . . . . . . . . . . . . . . 15
4. Signing Objects . . . . . . . . . . . . . . . . . . . . . . . 18
4.1. Signing with One or More Signers . . . . . . . . . . . . 18
4.2. Signing with One Signer . . . . . . . . . . . . . . . . . 20
4.3. Externally Supplied Data . . . . . . . . . . . . . . . . 21
4.4. Signing and Verification Process . . . . . . . . . . . . 22
5. Counter Signatures . . . . . . . . . . . . . . . . . . . . . 24
5.1. Full Countersignatures . . . . . . . . . . . . . . . . . 24
5.2. Abbreviated Countersignatures . . . . . . . . . . . . . . 25
6. Encryption Objects . . . . . . . . . . . . . . . . . . . . . 26
6.1. Enveloped COSE Structure . . . . . . . . . . . . . . . . 26
6.1.1. Content Key Distribution Methods . . . . . . . . . . 28
6.2. Single Recipient Encrypted . . . . . . . . . . . . . . . 28
6.3. How to Encrypt and Decrypt for AEAD Algorithms . . . . . 29
6.4. How to Encrypt and Decrypt for AE Algorithms . . . . . . 31
7. MAC Objects . . . . . . . . . . . . . . . . . . . . . . . . . 33
7.1. MACed Message with Recipients . . . . . . . . . . . . . . 33
7.2. MACed Messages with Implicit Key . . . . . . . . . . . . 34
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