Encrypted Key Transport for DTLS and Secure RTP
draft-ietf-perc-srtp-ekt-diet-09

Document Type Active Internet-Draft (perc WG)
Last updated 2018-11-01 (latest revision 2018-10-17)
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: April 20, 2019                                      Ericsson AB
                                                               D. McGrew
                                                           Cisco Systems
                                                                 D. Wing

                                                            F. Andreason
                                                           Cisco Systems
                                                        October 17, 2018

            Encrypted Key Transport for DTLS and Secure RTP
                    draft-ietf-perc-srtp-ekt-diet-09

Abstract

   Encrypted Key Transport (EKT) is an extension to DTLS (Datagram
   Transport Layer Security) 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

   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 20, 2019.

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Jennings, et al.         Expires April 20, 2019                 [Page 1]
Internet-Draft                  EKT SRTP                    October 2018

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   (https://trustee.ietf.org/license-info) in effect on the date of
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Conventions Used In This Document . . . . . . . . . . . . . .   4
   4.  Encrypted Key Transport . . . . . . . . . . . . . . . . . . .   4
     4.1.  EKTField 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 . . . . . . . . . . . . . . . . . . . . . . . . .  11
       4.4.1.  Ciphers . . . . . . . . . . . . . . . . . . . . . . .  12
       4.4.2.  Defining New EKT Ciphers  . . . . . . . . . . . . . .  12
     4.5.  Synchronizing Operation . . . . . . . . . . . . . . . . .  12
     4.6.  Transport . . . . . . . . . . . . . . . . . . . . . . . .  13
     4.7.  Timing and Reliability Consideration  . . . . . . . . . .  13
   5.  Use of EKT with DTLS-SRTP . . . . . . . . . . . . . . . . . .  14
     5.1.  DTLS-SRTP Recap . . . . . . . . . . . . . . . . . . . . .  14
     5.2.  SRTP EKT Key Transport Extensions to DTLS-SRTP  . . . . .  14
       5.2.1.  Negotiating an EKTCipher  . . . . . . . . . . . . . .  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 . . . . . . . . . . . . . . . . . . . . .  20
     7.1.  EKT Message Types . . . . . . . . . . . . . . . . . . . .  20
     7.2.  EKT Ciphers . . . . . . . . . . . . . . . . . . . . . . .  20
     7.3.  TLS Extensions  . . . . . . . . . . . . . . . . . . . . .  21
     7.4.  TLS Handshake Type  . . . . . . . . . . . . . . . . . . .  21
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  21
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  22
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