CoAP: Echo, Request-Tag, and Token Processing
draft-ietf-core-echo-request-tag-05
CoRE Working Group C. Amsuess
Internet-Draft
Updates: 7252 (if approved) J. Mattsson
Intended status: Standards Track G. Selander
Expires: November 7, 2019 Ericsson AB
May 06, 2019
CoAP: Echo, Request-Tag, and Token Processing
draft-ietf-core-echo-request-tag-05
Abstract
This document specifies enhancements to the Constrained Application
Protocol (CoAP) that mitigate security issues in particular use
cases. The Echo option enables a CoAP server to verify the freshness
of a request or to force a client to demonstrate reachability at its
claimed network address. The Request-Tag option allows the CoAP
server to match Block-Wise message fragments belonging to the same
request. The updated Token processing requirements for clients
ensure secure binding of responses to requests when CoAP is used with
security.
Status of This Memo
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This Internet-Draft will expire on November 7, 2019.
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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 . . . . . . . . . . . . . . . . . . . . . . 10
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 . . . . . . . . . . . . . . . . . . . . . . 14
3.4.1. Body Integrity Based on Payload Integrity . . . . . . 14
3.4.2. Multiple Concurrent Blockwise Operations . . . . . . 15
3.4.3. Simplified Block-Wise Handling for Constrained
Proxies . . . . . . . . . . . . . . . . . . . . . . . 16
3.5. Rationale for the Option Properties . . . . . . . . . . . 16
3.6. Rationale for Introducing the Option . . . . . . . . . . 16
4. Block2 / ETag Processing . . . . . . . . . . . . . . . . . . 17
5. Token Processing . . . . . . . . . . . . . . . . . . . . . . 17
6. Security Considerations . . . . . . . . . . . . . . . . . . . 17
7. Privacy Considerations . . . . . . . . . . . . . . . . . . . 18
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 19
9.1. Normative References . . . . . . . . . . . . . . . . . . 19
9.2. Informative References . . . . . . . . . . . . . . . . . 19
Appendix A. Methods for Generating Echo Option Values . . . . . 21
Appendix B. Request-Tag Message Size Impact . . . . . . . . . . 22
Appendix C. Change Log . . . . . . . . . . . . . . . . . . . . . 22
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24
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