Intersectionpolicy private mutual authentication from authorized private set intersection Private mutual authentication (PMA) enables twoway anonymous authentication between two users certified by the same trusted group authority. Most existing PMA schemes focus on acquiring a relatively onefold authentication policy that ensures affiliationhiding or designated singleattribute matching. However, in practice, users are typically provided with multiple attributes. In addition to the affiliationhiding requirement, how to effectively achieve a more flexible authentication policy for multiattribute applications remains a challenging issue. The intersection policy for authentication is also required when the attribute intersection is not an empty set or its cardinality is no less than a threshold value. To solve the above problems, we first propose an optimal authorized private set intersection protocol with forward security based on identitybased encryption and then design a new PMA protocol with intersectionpolicy called IPPMA, which provides a simple solution for secret handshakes between two members (holding multiple attributes) from the same organization. Formal security analyses proved that our two proposed protocols are secure in the random oracle model. Empirical tests demonstrated that the IPPMA protocol is optimized with linear complexity and may be more suitable for resourceconstrained applications.

Construction and Evaluation of AttributeBased ChallengeandResponse Authentication on Asymmetric Bilinear Map We propose a construction of an attributebased authentication scheme (ABAuth). Our ABAuth is a challengeandresponse protocol which uses an attributebased keyencapsulation mechanisum (ABKEM). The ABKEM is basically the one proposed by OstrovskySahaiWaters (ACMCCS 2007), but in contrast to the original ABKEM our ABKEM is based on an asymmetric bilinear map for better computational efficiency. We also give a proof of onewayCCA security of ABKEM in the asymmetric case, which leads to concurrent maninthemiddle security of ABAuth. We note that the selective security is often enough for the case of authentication in contrast to the case of encryption. Then we evaluate our ABAuth by implementation as well as by discussion. We use the TEPLA library TEPLA for the asymmetric bilinear map that is Type3 pairing on the BN curve.