An unconditionally secure multi-round revocation scheme using secret sharing

The revocation schemes are usually used for broadcast encryption and multicast key management. We present a Shamir's polynomial secret sharing based revocation scheme that enable many revocation rounds and has t(2) revocation capability in each round. Our scheme has some notable properties as compared with the other precious schemes: (1) Our multi-round revocation scheme is unconditionally secure other than computationally secure; (2) Our scheme promotes the revocation capability from t users to t(2) users in every round, and is secure against any coalition of all the revoked users. (3) Each user only restores the constant personal keys during the whole session, and the overhead of computation and communication is only dependant on the degree of the secret sharing polynomial regardless of the size of the group.