Network Working Group V. Lehtovirta
Internet-Draft Ericsson Research NomadicLab
Intended status: Informational February 26, 2007
Expires: August 30, 2007
Infrastructure aspects to media security
draft-lehtovirta-rtpsec-infra-00
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Internet-Draft Infrastructure aspects to media security February 2007
Abstract
This document discusses some infrastructure aspects that should be
considered in the media security requirements work.
Table of Contents
1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Termination of media security in a gateway . . . . . . . . . . 5
4. Using shared keys to provide media security . . . . . . . . . 6
5. Setting up media security with the help of a third party . . . 7
6. Termination of media streams in different devices . . . . . . 8
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1. Normative References . . . . . . . . . . . . . . . . . . . 10
8.2. Informative References . . . . . . . . . . . . . . . . . . 10
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 11
Intellectual Property and Copyright Statements . . . . . . . . . . 12
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1. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
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2. Introduction
Requirements related to the ongoing media security work are discussed
for example in [I-D.wing-media-security-requirements].
This document discusses some infrastructure aspects that should be
considered in the media security requirements work.
These aspects are:
o Termination of media security in a gateway
o Using shared keys to provide media security
o Setting up media security with the help of a third party
o Termination of media streams in different devices
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3. Termination of media security in a gateway
A typical case of using media security is the one where two entities
are having a VoIP conversation over IP capable networks. However,
there are cases where the other end of the communication is not
connected to an IP capable network. In this kind of setting, there
needs to be some kind of gateway at the edge of the IP network which
converts the VoIP conversation to format understood by the other
network. An example of such gateway is a PSTN gateway sitting at the
edge of IP and PSTN networks.
If media security (e.g. SRTP protection) is employed in this kind of
gateway-setting, then media security and the related key management
needs to be terminated at the gateway. The other network (e.g.
PSTN) may have its own measures to protect the communication, but
this means that from media security point of view the media security
is not employed end-to-end between the communicating entities.
Therefore, media security solutions should cover the cases where
media security is not employed end-to-end but is terminated in a
gateway.
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4. Using shared keys to provide media security
There are environments where the communicating endpoints set up
shared keys with the network infrastructure. An example of such
environment is the widely deployed GSM system and its 3G successor,
the UMTS. It would be beneficial if the shared keys between the
endpoints and the network infrastructure in these kind of systems
could be re-used to provide shared keys also between the
communicating endpoints.
Therefore, it might be justified to consider using shared keys in
addition to public keys to provide media security in some
environments.
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5. Setting up media security with the help of a third party
Setting up a secured connection to an arbitrary peer requires that
the communicating entities have in some way agreed on key management
credentials, e.g. shared keys or certificates. From scalability
point of view it is in practice not feasible to achieve this to an
arbitrary peer without the help of some third party providing the
credentials.
To enable a scalable solution that allows to set up a secure
connection to an arbitrary peer seems to require the help of some
third party.
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6. Termination of media streams in different devices
In some cases, different media streams might be terminated in
different devices. For example, the video part of a multimedia
session could terminate in one device, while the audio part would
terminate in another device. It should be possible to set up media
security efficiently in such scenarios.
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7. Security Considerations
None.
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8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
8.2. Informative References
[I-D.wing-media-security-requirements]
Wing, D., "Media Security Requirements",
draft-wing-media-security-requirements-00 (work in
progress), October 2006.
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Author's Address
Vesa Lehtovirta
Ericsson Research NomadicLab
JORVAS FIN-02420
FINLAND
Phone: +358 9 299 1
Email: vesa.lehtovirta@ericsson.com
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