With Common IMS it has become possible to use IMS over a wide variety of access networks. These access networks
provide security of varying strengths, or, in some cases, no security at all. It is therefore desirable to have a standard for IMS media plane security, which provides uniform protection of IMS media against eavesdropping and undetected modification across access networks.
Furthermore, media transport in the core network, although generally less vulnerable than in the access network, may also be realised in varying ways with different guarantees of protection. It is therefore also desirable to have a standard for IMS media plane security, which guarantees protection of IMS media against eavesdropping and undetected modification in an end-to-end (e2e) fashion between two terminal devices.
This TS presents IMS media plane security for RTP based media which is designed to meet the following
three main objectives:
to provide security for media usable across all access networks
to provide an end-to-end (e2e) media security solution to satisfy major user categories
to provide end-to-end (e2e) media security for important user groups like enterprises, National Security and
Public Safety (NSPS) organizations and different government authorities who may have weaker trust in the
inherent IMS security and/or may desire to provide their own key management service.
The media plane security in this release of the TS is based on the well established protocol SRTP. Key management
solutions for SRTP are defined in this specification.
The media plane security for MSRP, used in session-based messaging, is based on TLS. TLS is also used to protect
BFCP. Key management solutions for MSRP and BFCP security are defined in this specification.
Two normative Annexes to the present document address IMS media plane security for immediate messaging and
conferencing, respectively. The media plane security for session-based messaging is addressed in the main body of this specification.