Ephemeral Diffie-Hellman Over COSE (EDHOC)
draft-selander-ace-cose-ecdhe-08

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ACE Working Group                                            G. Selander
Internet-Draft                                               J. Mattsson
Intended status: Standards Track                            F. Palombini
Expires: September 6, 2018                                   Ericsson AB
                                                          March 05, 2018

               Ephemeral Diffie-Hellman Over COSE (EDHOC)
                    draft-selander-ace-cose-ecdhe-08

Abstract

   This document specifies Ephemeral Diffie-Hellman Over COSE (EDHOC), a
   compact, and lightweight authenticated Diffie-Hellman key exchange
   with ephemeral keys that can be used over any layer.  EDHOC messages
   are encoded with CBOR and COSE, allowing reuse of existing libraries.

Status of This Memo

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   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on September 6, 2018.

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   document authors.  All rights reserved.

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Selander, et al.        Expires September 6, 2018               [Page 1]
Internet-Draft Ephemeral Diffie-Hellman Over COSE (EDHOC)     March 2018

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Protocol Overview . . . . . . . . . . . . . . . . . . . . . .   3
   3.  EDHOC Overview  . . . . . . . . . . . . . . . . . . . . . . .   5
     3.1.  Formatting of the Ephemeral Public Keys . . . . . . . . .   6
     3.2.  Key Derivation  . . . . . . . . . . . . . . . . . . . . .   6
   4.  EDHOC Authenticated with Asymmetric Keys  . . . . . . . . . .   8
     4.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .   8
     4.2.  EDHOC Message 1 . . . . . . . . . . . . . . . . . . . . .   9
     4.3.  EDHOC Message 2 . . . . . . . . . . . . . . . . . . . . .  11
     4.4.  EDHOC Message 3 . . . . . . . . . . . . . . . . . . . . .  14
   5.  EDHOC Authenticated with Symmetric Keys . . . . . . . . . . .  15
     5.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .  15
     5.2.  EDHOC Message 1 . . . . . . . . . . . . . . . . . . . . .  16
     5.3.  EDHOC Message 2 . . . . . . . . . . . . . . . . . . . . .  19
     5.4.  EDHOC Message 3 . . . . . . . . . . . . . . . . . . . . .  21
   6.  Error Handling  . . . . . . . . . . . . . . . . . . . . . . .  22
     6.1.  Error Message Format  . . . . . . . . . . . . . . . . . .  22
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  22
     7.1.  The Well-Known URI Registry . . . . . . . . . . . . . . .  22
     7.2.  Media Types Registry  . . . . . . . . . . . . . . . . . .  23
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  24
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  26
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  26
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  26
     10.2.  Informative References . . . . . . . . . . . . . . . . .  27
   Appendix A.  Test Vectors . . . . . . . . . . . . . . . . . . . .  28
   Appendix B.  PSK Chaining . . . . . . . . . . . . . . . . . . . .  28
   Appendix C.  EDHOC with CoAP and OSCORE . . . . . . . . . . . . .  28
     C.1.  Transferring EDHOC in CoAP  . . . . . . . . . . . . . . .  28
     C.2.  Deriving an OSCORE context from EDHOC . . . . . . . . . .  29
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  30

1.  Introduction

   Security at the application layer provides an attractive option for
   protecting Internet of Things (IoT) deployments, for example where
   transport layer security is not sufficient
   [I-D.hartke-core-e2e-security-reqs] or where the protocol needs to