Coexistence between TISPAN and 3GPP authentication schemes
The present document studies from a security point of view the coexistence between TISPAN authentication methods (as specified in TISPAN release 1) and existing 3GPP authentication schemes, i.e. both the IMS AKA (as specified in TS 33.203 [5] and TS 24.229 [4]) and the early IMS security (as specified in TR 33.978 [6]). This document also aims to provide solutions to handle potential compatibility issues. These issues are listed in detail in section 5 of this document.
This document is meant to ensure that the same IMS core network entities can be used to support both 3GPP and TISPAN authentication schemes. In this context, rules are developed how an x‑CSCF can decide from a registration request which authentication scheme to apply. If these rules are not adhered to compatibility problems may arise.