Echo and Request-Tag
draft-ietf-core-echo-request-tag-02

Document Type Active Internet-Draft (core WG)
Last updated 2018-06-29
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: December 31, 2018                                   Ericsson AB
                                                           June 29, 2018

                          Echo and Request-Tag
                  draft-ietf-core-echo-request-tag-02

Abstract

   This document specifies several 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 [RFC7252].  The updated Token processing
   ensures secure binding of responses to requests.

Status of This Memo

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   This Internet-Draft will expire on December 31, 2018.

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
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   (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 December 31, 2018               [Page 1]
Internet-Draft            Echo and Request-Tag                 June 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 . . . . . . . . . . . .   3
     1.3.  Request-Response Binding  . . . . . . . . . . . . . . . .   4
     1.4.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   5
   2.  The Echo Option . . . . . . . . . . . . . . . . . . . . . . .   5
     2.1.  Option Format . . . . . . . . . . . . . . . . . . . . . .   6
     2.2.  Echo Processing . . . . . . . . . . . . . . . . . . . . .   6
     2.3.  Applications  . . . . . . . . . . . . . . . . . . . . . .   9
   3.  The Request-Tag Option  . . . . . . . . . . . . . . . . . . .  10
     3.1.  Option Format . . . . . . . . . . . . . . . . . . . . . .  10
     3.2.  Request-Tag processing by servers . . . . . . . . . . . .  11
     3.3.  Setting the Request-Tag . . . . . . . . . . . . . . . . .  12
     3.4.  Applications  . . . . . . . . . . . . . . . . . . . . . .  12
       3.4.1.  Body Integrity Based on Payload Integrity . . . . . .  12
       3.4.2.  Multiple Concurrent Blockwise Operations  . . . . . .  13
       3.4.3.  Simplified block-wise Handling for constrained
               proxies . . . . . . . . . . . . . . . . . . . . . . .  14
     3.5.  Rationale for the option properties . . . . . . . . . . .  14
     3.6.  Rationale for introducing the option  . . . . . . . . . .  15
   4.  Block2 / ETag Processing  . . . . . . . . . . . . . . . . . .  15
   5.  Token Processing  . . . . . . . . . . . . . . . . . . . . . .  15
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  15
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  16
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  17
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  17
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  17
   Appendix A.  Methods for Generating Echo Option Values  . . . . .  18
   Appendix B.  Request-Tag Message Size Impact  . . . . . . . . . .  19
   Appendix C.  Change Log . . . . . . . . . . . . . . . . . . . . .  20
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  21

1.  Introduction

   The initial Constrained Application Protocol (CoAP) suite of
   specifications ([RFC7252], [RFC7641], and [RFC7959]) was designed
   with the assumption that security could be provided on a separate
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