An Authenticated Group Key Transfer Protocol Based on Secret Sharing

In traditional group key transfer protocol, the key generation center randomly selects a session key and then transports it that has been encrypted by another secret key. Afterwards, scholars construct authenticated key transfer protocols based on secret sharing instead of encryption algorithm. One typical protocol of this style is built by using the secret sharing scheme based on Language's interpolation polynomial. In this paper, we utilize an optimized secret sharing scheme instead of Language's interpolation polynomial. We provide mutual authentication to ensure that only the authorized group members can recover the right session key. What's more, all participants only need to store one secret share for all sessions. Besides, the change of the group members has no effect on the validity of the existing shares, which means the existing shares possess the excellent characteristic “one time assign, many times apply”.