Key Management Extensions for Session Description Protocol (SDP) and Real Time Streaming Protocol (RTSP)
RFC 4567
Network Working Group J. Arkko
Request for Comments: 4567 F. Lindholm
Category: Standards Track M. Naslund
K. Norrman
Ericsson
E. Carrara
Royal Institute of Technology
July 2006
Key Management Extensions for Session Description
Protocol (SDP) and Real Time Streaming Protocol (RTSP)
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2006).
Abstract
This document defines general extensions for Session Description
Protocol (SDP) and Real Time Streaming Protocol (RTSP) to carry
messages, as specified by a key management protocol, in order to
secure the media. These extensions are presented as a framework, to
be used by one or more key management protocols. As such, their use
is meaningful only when complemented by an appropriate key management
protocol.
General guidelines are also given on how the framework should be used
together with SIP and RTSP. The usage with the Multimedia Internet
KEYing (MIKEY) key management protocol is also defined.
Arkko, et al. Standards Track [Page 1]
RFC 4567 Key Management Extensions for SDP and RTSP July 2006
Table of Contents
1. Introduction ....................................................3
1.1. Notational Conventions .....................................4
2. Applicability ...................................................4
3. Extensions to SDP and RTSP ......................................5
3.1. SDP Extensions .............................................5
3.2. RTSP Extensions ............................................6
4. Usage with SDP, SIP, RTSP, and SAP ..............................7
4.1. Use of SDP .................................................8
4.1.1. General Processing ..................................8
4.1.2. Use of SDP with Offer/Answer and SIP ...............10
4.1.3. Use of SDP with SAP ................................13
4.1.4. Bidding-Down Attack Prevention .....................13
4.2. RTSP Usage ................................................14
5. Example Scenarios ..............................................17
5.1. Example 1 (SIP/SDP) .......................................17
5.2. Example 2 (SDP) ...........................................18
5.3. Example 3 (RTSP) ..........................................18
5.4. Example 4 (RTSP) ..........................................20
6. Adding Further Key Management Protocols ........................21
7. Integration of MIKEY ...........................................22
7.1. MIKEY Interface ...........................................22
8. Security Considerations ........................................23
9. IANA Considerations ............................................25
9.1. SDP Attribute Registration ................................25
9.2. RTSP Registration .........................................26
9.3. Protocol Identifier Registration ..........................26
10. Acknowledgements ..............................................27
11. References ....................................................27
11.1. Normative References .....................................27
11.2. Informative References ...................................28
Arkko, et al. Standards Track [Page 2]
RFC 4567 Key Management Extensions for SDP and RTSP July 2006
1. Introduction
There has recently been work to define a security profile for the
protection of real-time applications running over RTP, [SRTP].
However, a security protocol needs a key management solution to
exchange keys and security parameters, manage and refresh keys, etc.
A key management protocol is executed prior to the security
protocol's execution. The key management protocol's main goal is to,
in a secure and reliable way, establish a security association for
the security protocol. This includes one or more cryptographic keys
and the set of necessary parameters for the security protocol, e.g.,
cipher and authentication algorithms to be used. The key management
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