Echo and Request-Tag
draft-ietf-core-echo-request-tag-03

Document Type Active Internet-Draft (core WG)
Last updated 2018-10-22
Replaces draft-amsuess-core-repeat-request-tag
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CoRE Working Group                                            C. Amsuess
Internet-Draft
Updates: 7252 (if approved)                                  J. Mattsson
Intended status: Standards Track                             G. Selander
Expires: April 25, 2019                                      Ericsson AB
                                                        October 22, 2018

                          Echo and Request-Tag
                  draft-ietf-core-echo-request-tag-03

Abstract

   This document specifies security enhancements to the Constrained
   Application Protocol (CoAP).  Two optional extensions are defined:
   the Echo option and the Request-Tag option.  Each of these options
   provide additional features to CoAP and protects against certain
   attacks.  The document also updates the processing requirements on
   the Token of RFC 7252.  The updated Token processing ensures secure
   binding of responses to requests.

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 April 25, 2019.

Copyright Notice

   Copyright (c) 2018 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

Amsuess, et al.          Expires April 25, 2019                 [Page 1]
Internet-Draft            Echo and Request-Tag              October 2018

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

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Request Freshness . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Fragmented Message Body Integrity . . . . . . . . . . . .   4
     1.3.  Request-Response Binding  . . . . . . . . . . . . . . . .   4
     1.4.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   5
   2.  The Echo Option . . . . . . . . . . . . . . . . . . . . . . .   6
     2.1.  Option Format . . . . . . . . . . . . . . . . . . . . . .   6
     2.2.  Echo Processing . . . . . . . . . . . . . . . . . . . . .   7
     2.3.  Applications  . . . . . . . . . . . . . . . . . . . . . .   9
   3.  The Request-Tag Option  . . . . . . . . . . . . . . . . . . .  11
     3.1.  Option Format . . . . . . . . . . . . . . . . . . . . . .  11
     3.2.  Request-Tag Processing by Servers . . . . . . . . . . . .  12
     3.3.  Setting the Request-Tag . . . . . . . . . . . . . . . . .  13
     3.4.  Applications  . . . . . . . . . . . . . . . . . . . . . .  13
       3.4.1.  Body Integrity Based on Payload Integrity . . . . . .  13
       3.4.2.  Multiple Concurrent Blockwise Operations  . . . . . .  14
       3.4.3.  Simplified Block-Wise Handling for Constrained
               Proxies . . . . . . . . . . . . . . . . . . . . . . .  15
     3.5.  Rationale for the Option Properties . . . . . . . . . . .  15
     3.6.  Rationale for Introducing the Option  . . . . . . . . . .  16
   4.  Block2 / ETag Processing  . . . . . . . . . . . . . . . . . .  16
   5.  Token Processing  . . . . . . . . . . . . . . . . . . . . . .  16
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  16
   7.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .  17
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  18
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  18
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  18
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  18
   Appendix A.  Methods for Generating Echo Option Values  . . . . .  20
   Appendix B.  Request-Tag Message Size Impact  . . . . . . . . . .  21
   Appendix C.  Change Log . . . . . . . . . . . . . . . . . . . . .  21
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  22
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  22

1.  Introduction

   The initial Constrained Application Protocol (CoAP) suite of
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