A Solution Framework for Private Media in Privacy Enhanced RTP Conferencing
draft-ietf-perc-private-media-framework-09

Document Type Active Internet-Draft (perc WG)
Last updated 2019-03-27 (latest revision 2019-02-19)
Replaces draft-jones-perc-private-media-framework
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Network Working Group                                           P. Jones
Internet-Draft                                                     Cisco
Intended status: Standards Track                               D. Benham
Expires: August 23, 2019                                       C. Groves
                                                             Independent
                                                       February 19, 2019

     A Solution Framework for Private Media in Privacy Enhanced RTP
                              Conferencing
               draft-ietf-perc-private-media-framework-09

Abstract

   This document describes a solution framework for ensuring that media
   confidentiality and integrity are maintained end-to-end within the
   context of a switched conferencing environment where media
   distributors are not trusted with the end-to-end media encryption
   keys.  The solution aims to build upon existing security mechanisms
   defined for the real-time transport protocol (RTP).

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 August 23, 2019.

Copyright Notice

   Copyright (c) 2019 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

Jones, et al.            Expires August 23, 2019                [Page 1]
Internet-Draft           Private Media Framework           February 2019

   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Conventions Used in This Document . . . . . . . . . . . . . .   3
   3.  PERC Entities and Trust Model . . . . . . . . . . . . . . . .   5
     3.1.  Untrusted Entities  . . . . . . . . . . . . . . . . . . .   5
       3.1.1.  Media Distributor . . . . . . . . . . . . . . . . . .   6
       3.1.2.  Call Processing . . . . . . . . . . . . . . . . . . .   6
     3.2.  Trusted Entities  . . . . . . . . . . . . . . . . . . . .   7
       3.2.1.  Endpoint  . . . . . . . . . . . . . . . . . . . . . .   7
       3.2.2.  Key Distributor . . . . . . . . . . . . . . . . . . .   7
   4.  Framework for PERC  . . . . . . . . . . . . . . . . . . . . .   7
     4.1.  End-to-End and Hop-by-Hop Authenticated Encryption  . . .   8
     4.2.  E2E Key Confidentiality . . . . . . . . . . . . . . . . .   9
     4.3.  E2E Keys and Endpoint Operations  . . . . . . . . . . . .   9
     4.4.  HBH Keys and Per-hop Operations . . . . . . . . . . . . .  10
     4.5.  Key Exchange  . . . . . . . . . . . . . . . . . . . . . .  10
       4.5.1.  Initial Key Exchange and Key Distributor  . . . . . .  11
       4.5.2.  Key Exchange during a Conference  . . . . . . . . . .  12
   5.  Authentication  . . . . . . . . . . . . . . . . . . . . . . .  13
     5.1.  Identity Assertions . . . . . . . . . . . . . . . . . . .  13
     5.2.  Certificate Fingerprints in Session Signaling . . . . . .  14
     5.3.  Conferences Identification  . . . . . . . . . . . . . . .  14
   6.  PERC Keys . . . . . . . . . . . . . . . . . . . . . . . . . .  14
     6.1.  Key Inventory and Management Considerations . . . . . . .  15
     6.2.  DTLS-SRTP Exchange Yields HBH Keys  . . . . . . . . . . .  15
     6.3.  The Key Distributor Transmits the KEK (EKT Key) . . . . .  16
     6.4.  Endpoints fabricate an SRTP Master Key  . . . . . . . . .  17
     6.5.  Summary of Key Types and Entity Possession  . . . . . . .  17
   7.  Encrypted Media Packet Format . . . . . . . . . . . . . . . .  18
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  19
     8.1.  Third Party Attacks . . . . . . . . . . . . . . . . . . .  19
     8.2.  Media Distributor Attacks . . . . . . . . . . . . . . . .  20
       8.2.1.  Denial of service . . . . . . . . . . . . . . . . . .  20
       8.2.2.  Replay Attack . . . . . . . . . . . . . . . . . . . .  21
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