Strongly Secure Two-Pass Attribute-Based Authenticated Key Exchange

In this paper, we present a two-party attribute-based authenticated key exchange scheme secure in the stronger security model than the previous models. Our strong security model is a natural extension of the eCK model, which is for PKI-based authenticated key exchange, into the attribute-based setting. We prove the security of our scheme under the gap Bilinear Diffie-Hellman assumption. Moreover, while the previous scheme needs the three-pass interaction between parties, our scheme needs only the two-pass interaction. In a practical sense, we can use any string as an attribute in our scheme because the setup algorithm of our scheme does not depend on the number of attribute candidates (i.e., the setup algorithm outputs constant size parameters).