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 | IETF | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 4568 (Proposed Standard) | |
Action Holders |
(None)
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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 ..............................25Show full document text