The present document studies use cases, requirements and candidate solutions for protecting the IMS media plane against eavesdropping and undetected modification. Currently IMS media protection relies on security provided at the lower layers. With Common IMS, it has become possible to use IMS over a wide variety of access networks which provide varying levels of security and in some cases no security at all. It is therefore desirable to study solutions for securing the IMS media plane in a uniform manner across all 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 levels of security. Therefore, the present document also studies solutions for end-to-end protection of IMS media.

The following documents contain provisions which, through reference in this text, constitute provisions of the present document.

• References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.