CBOR Algoritms for Object Signing and Encryption (COSE)
draft-schaad-cose-rfc8152bis-algs-00

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Last updated 2018-08-22
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COSE Working Group                                             J. Schaad
Internet-Draft                                            August Cellars
Obsoletes: 8152 (if approved)                            August 22, 2018
Intended status: Standards Track
Expires: February 23, 2019

        CBOR Algoritms for Object Signing and Encryption (COSE)
                  draft-schaad-cose-rfc8152bis-algs-00

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.  COSE additionally describes how to represent
   cryptographic keys using CBOR.

   In this specification the conventions for the use of a number of
   cryptographic algorithms with COSE.  The details of the structure of
   COSE are defined in [I-D.schaad-cose-rfc8152bis-struct].

   This document along with [I-D.schaad-cose-rfc8152bis-struct]
   obsoletes RFC8152.

Status of This Memo

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

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   This Internet-Draft will expire on February 23, 2019.

Schaad                  Expires February 23, 2019               [Page 1]
Internet-Draft               COSE Algorithms                 August 2018

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.1.  Requirements Terminology  . . . . . . . . . . . . . . . .   4
     1.2.  Document Terminology  . . . . . . . . . . . . . . . . . .   4
   2.  Signature Algorithms  . . . . . . . . . . . . . . . . . . . .   5
     2.1.  ECDSA . . . . . . . . . . . . . . . . . . . . . . . . . .   5
       2.1.1.  Security Considerations . . . . . . . . . . . . . . .   6
     2.2.  Edwards-Curve Digital Signature Algorithms (EdDSAs) . . .   7
       2.2.1.  Security Considerations . . . . . . . . . . . . . . .   8
   3.  Message Authentication Code (MAC) Algorithms  . . . . . . . .   8
     3.1.  Hash-Based Message Authentication Codes (HMACs) . . . . .   8
       3.1.1.  Security Considerations . . . . . . . . . . . . . . .  10
     3.2.  AES Message Authentication Code (AES-CBC-MAC) . . . . . .  10
       3.2.1.  Security Considerations . . . . . . . . . . . . . . .  11
   4.  Content Encryption Algorithms . . . . . . . . . . . . . . . .  11
     4.1.  AES GCM . . . . . . . . . . . . . . . . . . . . . . . . .  11
       4.1.1.  Security Considerations . . . . . . . . . . . . . . .  12
     4.2.  AES CCM . . . . . . . . . . . . . . . . . . . . . . . . .  13
       4.2.1.  Security Considerations . . . . . . . . . . . . . . .  15
     4.3.  ChaCha20 and Poly1305 . . . . . . . . . . . . . . . . . .  15
       4.3.1.  Security Considerations . . . . . . . . . . . . . . .  16
   5.  Key Derivation Functions (KDFs) . . . . . . . . . . . . . . .  16
     5.1.  HMAC-Based Extract-and-Expand Key Derivation Function
           (HKDF)  . . . . . . . . . . . . . . . . . . . . . . . . .  16
     5.2.  Context Information Structure . . . . . . . . . . . . . .  18
   6.  Content Key Distribution Methods  . . . . . . . . . . . . . .  23
     6.1.  Direct Key  . . . . . . . . . . . . . . . . . . . . . . .  23
       6.1.1.  Security Considerations . . . . . . . . . . . . . . .  24
     6.2.  Direct Key with KDF . . . . . . . . . . . . . . . . . . .  24
       6.2.1.  Security Considerations . . . . . . . . . . . . . . .  25
     6.3.  AES Key Wrap  . . . . . . . . . . . . . . . . . . . . . .  26
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