Securing the RTP Framework: Why RTP Does Not Mandate a Single Media Security Solution
RFC 7202
Internet Engineering Task Force (IETF) C. Perkins
Request for Comments: 7202 University of Glasgow
Category: Informational M. Westerlund
ISSN: 2070-1721 Ericsson
April 2014
Securing the RTP Framework:
Why RTP Does Not Mandate a Single Media Security Solution
Abstract
This memo discusses the problem of securing real-time multimedia
sessions. It also explains why the Real-time Transport Protocol
(RTP) and the associated RTP Control Protocol (RTCP) do not mandate a
single media security mechanism. This is relevant for designers and
reviewers of future RTP extensions to ensure that appropriate
security mechanisms are mandated and that any such mechanisms are
specified in a manner that conforms with the RTP architecture.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
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). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see 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/rfc7202.
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RFC 7202 Securing the RTP Framework April 2014
Copyright Notice
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This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. RTP Applications and Deployment Scenarios . . . . . . . . . . 3
3. RTP Media Security . . . . . . . . . . . . . . . . . . . . . 4
4. RTP Session Establishment and Key Management . . . . . . . . 5
5. On the Requirement for Strong Security in Framework Protocols 5
6. Securing the RTP Framework . . . . . . . . . . . . . . . . . 6
7. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . 8
8. Security Considerations . . . . . . . . . . . . . . . . . . . 8
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
10. Informative References . . . . . . . . . . . . . . . . . . . 8
1. Introduction
The Real-time Transport Protocol (RTP) [RFC3550] is widely used for
voice over IP, Internet television, video conferencing, and other
real-time and streaming media applications. Despite this use, the
basic RTP specification provides only limited options for media
security and defines no standard key exchange mechanism. Rather, a
number of extensions are defined that can provide confidentiality and
authentication of RTP media streams and RTP Control Protocol (RTCP)
messages. Other mechanisms define key exchange protocols. This memo
outlines why it is appropriate that multiple extension mechanisms are
defined rather than mandating a single security and keying mechanism
for all users of RTP.
The IETF policy "Strong Security Requirements for Internet
Engineering Task Force Standard Protocols" [RFC3365] (the so-called
"Danvers Doctrine") states that "we MUST implement strong security in
all protocols to provide for the all too frequent day when the
protocol comes into widespread use in the global Internet". The
security mechanisms defined for use with RTP allow these requirements
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RFC 7202 Securing the RTP Framework April 2014
to be met. However, since RTP is a protocol framework that is
suitable for a wide variety of use cases, there is no single security
mechanism that is suitable for every scenario. This memo outlines
why this is the case and discusses how users of RTP can meet the
requirement for strong security.
This document provides high-level guidance on how to handle security
issues for the various types of components within the RTP framework
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