Encrypted Key Transport for DTLS and Secure RTP
draft-ietf-perc-srtp-ekt-diet-06

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Last updated 2017-10-30
Replaces draft-jennings-perc-srtp-ekt-diet
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Network Working Group                                        C. Jennings
Internet-Draft                                             Cisco Systems
Intended status: Standards Track                             J. Mattsson
Expires: May 3, 2018                                         Ericsson AB
                                                               D. McGrew
                                                                 D. Wing
                                                            F. Andreason
                                                           Cisco Systems
                                                        October 30, 2017

            Encrypted Key Transport for DTLS and Secure RTP
                    draft-ietf-perc-srtp-ekt-diet-06

Abstract

   Encrypted Key Transport (EKT) is an extension to DTLS and Secure
   Real-time Transport Protocol (SRTP) that provides for the secure
   transport of SRTP master keys, rollover counters, and other
   information within SRTP.  This facility enables SRTP for
   decentralized conferences by distributing a common key to all of the
   conference endpoints.

Status of This Memo

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   This Internet-Draft will expire on May 3, 2018.

Copyright Notice

   Copyright (c) 2017 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
   (http://trustee.ietf.org/license-info) in effect on the date of

Jennings, et al.           Expires May 3, 2018                  [Page 1]
Internet-Draft                  EKT SRTP                    October 2017

   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Conventions Used In This Document . . . . . . . . . . . . . .   4
   4.  Encrypted Key Transport . . . . . . . . . . . . . . . . . . .   4
     4.1.  EKT Field Formats . . . . . . . . . . . . . . . . . . . .   5
     4.2.  Packet Processing and State Machine . . . . . . . . . . .   7
       4.2.1.  Outbound Processing . . . . . . . . . . . . . . . . .   8
       4.2.2.  Inbound Processing  . . . . . . . . . . . . . . . . .   9
     4.3.  Implementation Notes  . . . . . . . . . . . . . . . . . .  10
     4.4.  Ciphers . . . . . . . . . . . . . . . . . . . . . . . . .  10
       4.4.1.  Ciphers . . . . . . . . . . . . . . . . . . . . . . .  11
       4.4.2.  Defining New EKT Ciphers  . . . . . . . . . . . . . .  12
     4.5.  Synchronizing Operation . . . . . . . . . . . . . . . . .  12
     4.6.  Transport . . . . . . . . . . . . . . . . . . . . . . . .  12
     4.7.  Timing and Reliability Consideration  . . . . . . . . . .  12
   5.  Use of EKT with DTLS-SRTP . . . . . . . . . . . . . . . . . .  13
     5.1.  DTLS-SRTP Recap . . . . . . . . . . . . . . . . . . . . .  14
     5.2.  SRTP EKT Key Transport Extensions to DTLS-SRTP  . . . . .  14
       5.2.1.  Negotiating an EKT Cipher . . . . . . . . . . . . . .  16
       5.2.2.  Establishing an EKT Key . . . . . . . . . . . . . . .  16
     5.3.  Offer/Answer Considerations . . . . . . . . . . . . . . .  18
     5.4.  Sending the DTLS EKTKey Reliably  . . . . . . . . . . . .  18
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  18
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  19
     7.1.  EKT Message Types . . . . . . . . . . . . . . . . . . . .  19
     7.2.  EKT Ciphers . . . . . . . . . . . . . . . . . . . . . . .  20
     7.3.  TLS Extensions  . . . . . . . . . . . . . . . . . . . . .  21
     7.4.  TLS Handshake Type  . . . . . . . . . . . . . . . . . . .  21
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  21
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