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, where t is the degree of the secret sharing polynomial. 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 t2 users in every round. The property can lower the degree of the secret sharing polynomial, which helps to reduce the communications overhead and the cost of the computations. (3) Our scheme is secure against any coalition of all the revoked users. In addition, our scheme also keeps the properties of the other revocation using secret sharing: O(l) personal keys storage, the communication overhead and the cost of the computation are independent of the size of the group.