Framework for Establishing a Secure Real-time Transport Protocol (SRTP) Security Context Using Datagram Transport Layer Security (DTLS)
RFC 5763
Internet Engineering Task Force (IETF) J. Fischl
Request for Comments: 5763 Skype, Inc.
Category: Standards Track H. Tschofenig
ISSN: 2070-1721 Nokia Siemens Networks
E. Rescorla
RTFM, Inc.
May 2010
Framework for Establishing a Secure Real-time Transport Protocol (SRTP)
Security Context Using Datagram Transport Layer Security (DTLS)
Abstract
This document specifies how to use the Session Initiation Protocol
(SIP) to establish a Secure Real-time Transport Protocol (SRTP)
security context using the Datagram Transport Layer Security (DTLS)
protocol. It describes a mechanism of transporting a fingerprint
attribute in the Session Description Protocol (SDP) that identifies
the key that will be presented during the DTLS handshake. The key
exchange travels along the media path as opposed to the signaling
path. The SIP Identity mechanism can be used to protect the
integrity of the fingerprint attribute from modification by
intermediate proxies.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc5763.
Fischl, et al. Standards Track [Page 1]
RFC 5763 DTLS-SRTP Framework May 2010
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Table of Contents
1. Introduction ....................................................4
2. Overview ........................................................5
3. Motivation ......................................................7
4. Terminology .....................................................8
5. Establishing a Secure Channel ...................................8
6. Miscellaneous Considerations ...................................10
6.1. Anonymous Calls ...........................................10
6.2. Early Media ...............................................11
6.3. Forking ...................................................11
6.4. Delayed Offer Calls .......................................11
6.5. Multiple Associations .....................................11
6.6. Session Modification ......................................12
6.7. Middlebox Interaction .....................................12
6.7.1. ICE Interaction ....................................12
6.7.2. Latching Control without ICE .......................13
6.8. Rekeying ..................................................13
6.9. Conference Servers and Shared Encryptions Contexts ........13
6.10. Media over SRTP ..........................................14
6.11. Best Effort Encryption ...................................14
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