The purpose of this Recommendation is to describe an efficient and scalable, PKI-based hybrid security profile for version 2 or higher of ITU-T Rec. H.235.0. The hybrid security profile contained herein takes advantage of the security profiles in ITU-T Recs H.235.1 and H.235.2 by deploying digital signatures from ITU-T Rec. H.235.2 and deploying the baseline security profile from ITU-T Rec. H.235.1. In earlier versions of the H.235 sub-series, this profile was contained in Annex F/H.235. Appendices IV, V, VI to H.235.0 show the complete clause, figure, and table mapping between H.235 versions 3 and 4.