Provably Secure Certificateless Authenticated Asymmetric Group Key Agreement

摘要

Asymmetric group key agreement allows a group of members to establish a public group encryption key while each member has a different secret decryption key. Knowing the group encryption key, a sender can encrypt to the group members so that only the members can decrypt. This paper studies authenticated asymmetric group key agreement in certificateless public key cryptography. We formalize the security model of certificateless authenticated asymmetric group key agreement and capture typical attacks in the real world. We next present a strongly unforgeable stateful certificateless batch multi-signature scheme as building block and realize a one-round certificatless authenticated asymmetric group key agreement protocol to resist active attacks. Both the new multi-signature scheme and the resulting group key agreement protocol are shown to be secure under the well-established computational Diffie-Hellman and the k-Bilinear Diffie-Hellman exponent assumptions in the random oracle model, respectively.