Session Description Protocol (SDP) Security Descriptions for Media Streams
RFC 4568
| Document | Type | RFC - Proposed Standard (July 2006; Errata) | |
|---|---|---|---|
| Authors | Flemming Andreasen , Dan Wing , Mark Baugher | ||
| Last updated | 2020-09-18 | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 4568 (Proposed Standard) | |
| Action Holders |
(None)
|
||
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Jon Peterson | ||
| Send notices to | jo@acm.org, csp@csperkins.org | ||
Network Working Group F. Andreasen
Request for Comments: 4568 M. Baugher
Category: Standards Track D. Wing
Cisco Systems
July 2006
Session Description Protocol (SDP)
Security Descriptions for Media Streams
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 a Session Description Protocol (SDP)
cryptographic attribute for unicast media streams. The attribute
describes a cryptographic key and other parameters that serve to
configure security for a unicast media stream in either a single
message or a roundtrip exchange. The attribute can be used with a
variety of SDP media transports, and this document defines how to use
it for the Secure Real-time Transport Protocol (SRTP) unicast media
streams. The SDP crypto attribute requires the services of a data
security protocol to secure the SDP message.
Table of Contents
1. Introduction ....................................................3
2. Notational Conventions ..........................................5
3. Applicability ...................................................5
4. SDP "Crypto" Attribute and Parameters ...........................5
4.1. Tag ........................................................6
4.2. Crypto-Suite ...............................................6
4.3. Key Parameters .............................................7
4.4. Session Parameters .........................................8
4.5. Example ....................................................8
5. General Use of the crypto Attribute .............................9
5.1. Use with Offer/Answer ......................................9
5.1.1. Generating the Initial Offer - Unicast Streams ......9
Andreasen, et al. Standards Track [Page 1]
RFC 4568 SDP Security Descriptions July 2006
5.1.2. Generating the Initial Answer - Unicast Streams ....10
5.1.3. Processing of the Initial Answer - Unicast
Streams ............................................11
5.1.4. Modifying the Session ..............................11
5.2. Use Outside Offer/Answer ..................................11
5.3. General Backwards Compatibility Considerations ............12
6. SRTP Security Descriptions .....................................12
6.1. SRTP Key Parameter ........................................13
6.2. Crypto-Suites .............................................16
6.2.1. AES_CM_128_HMAC_SHA1_80 ............................16
6.2.2. AES_CM_128_HMAC_SHA1_32 ............................17
6.2.3. F8_128_HMAC_SHA1_80 ................................17
6.2.4. Adding New Crypto-Suite Definitions ................17
6.3. Session Parameters ........................................17
6.3.1. KDR=n ..............................................18
6.3.2. UNENCRYPTED_SRTCP and UNENCRYPTED_SRTP .............18
6.3.3. UNAUTHENTICATED_SRTP ...............................18
6.3.4. FEC_ORDER=order ....................................19
6.3.5. FEC_KEY=key-params .................................19
6.3.6. Window Size Hint (WSH) .............................19
6.3.7. Defining New SRTP Session Parameters ...............20
6.4. SRTP Crypto Context Initialization ........................20
6.4.1. Late Binding of One or More SSRCs to a
Crypto Context .....................................21
6.4.2. Sharing Cryptographic Contexts among
Sessions or SSRCs ..................................22
6.5. Removal of Crypto Contexts ................................23
7. SRTP-Specific Use of the Crypto Attribute ......................23
7.1. Use with Offer/Answer .....................................23
7.1.1. Generating the Initial Offer - Unicast Streams .....23
7.1.2. Generating the Initial Answer - Unicast Streams ....24
7.1.3. Processing of the Initial Answer - Unicast
Streams ............................................25
7.1.4. Modifying the Session ..............................25
Show full document text