This Recommendation provides the framework for mutual party authentication during H.225.0 RAS exchanges. The proof-of-possession methods described permit secure use of shared secrets such as passwords which, if used by themselves, would not provide sufficient security. Extensions to the framework to permit simultaneous negotiation of Transport Layer Security parameters for protection of a subsequent call signalling channel are also described. In earlier versions of the H.235 sub-series, this profile was contained in H.235 Annex H. Appendices IV, V, VI to H.235.0 show the complete clause, figure, and table mapping between H.235 versions 3 and 4.