CBOR Object Signing and Encryption (COSE) - Structures and Process
draft-ietf-cose-rfc8152bis-struct-01
COSE Working Group J. Schaad
Internet-Draft August Cellars
Obsoletes: 8152 (if approved) February 14, 2019
Intended status: Standards Track
Expires: August 18, 2019
CBOR Object Signing and Encryption (COSE) - Structures and Process
draft-ietf-cose-rfc8152bis-struct-01
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 August 18, 2019.
Schaad Expires August 18, 2019 [Page 1]
Internet-Draft COSE Structure February 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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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
4.5. Computing Counter Signatures . . . . . . . . . . . . . . 22
5. Encryption Objects . . . . . . . . . . . . . . . . . . . . . 23
5.1. Enveloped COSE Structure . . . . . . . . . . . . . . . . 23
5.1.1. Content Key Distribution Methods . . . . . . . . . . 25
5.2. Single Recipient Encrypted . . . . . . . . . . . . . . . 25
5.3. How to Encrypt and Decrypt for AEAD Algorithms . . . . . 26
5.4. How to Encrypt and Decrypt for AE Algorithms . . . . . . 28
6. MAC Objects . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.1. MACed Message with Recipients . . . . . . . . . . . . . . 30
6.2. MACed Messages with Implicit Key . . . . . . . . . . . . 31
6.3. How to Compute and Verify a MAC . . . . . . . . . . . . . 32
7. Key Objects . . . . . . . . . . . . . . . . . . . . . . . . . 33
7.1. COSE Key Common Parameters . . . . . . . . . . . . . . . 34
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