Anonymous Conference Key Distribution Scheme with Perfect Forward Security

Most anonymous Conference Key Distribution (CKD) systems cannot provide forward security, which is a very important property. Even though some CKD systems provide that property, they can only provide partial forward security, not perfect forward security. An identity-based CKD scheme with user anonymity is proposed in this paper. Under the one-way hash (OWH) [Wu T. C. (1997)]and bilinear Diffie-Hellman (BDH) [Cai Yong-quan, Wang Ya-li. (2007)] cryptographic assumptions, the proposed scheme is secure against passive attacks, impersonation attacks and conspiracy attacks. Moreover, by distributing a random number to the participants through the Private Key Generator (PKG), this scheme provides perfect forward security, that is, even if the private keys of all the participants (including the chairman) are compromised, the conference key contributed by the chairman in the past will not be compromised.