An efficient revocation scheme for stateless receivers

Abstract

A revocation scheme for stateless receivers enables the center to deliver information securely to the legitimate users over a public channel, where the receivers do not update their state from session to session. In this paper, we propose an efficient revocation scheme for stateless receivers. Our scheme uses a logical hierarchical key tree. Among previously proposed revocation schemes for stateless receivers, the SD scheme [10] is very efficient with respect to message length and Asano's schemes [1] are very efficient with respect to key storage. Using a binary key tree, our scheme has the same message length as the SD scheme and requires the storage of log n keys, whereas the SD scheme requires the storage of 1/2 log(2)n + 1/2 log n + 1 keys. Using an a-ary key tree, our scheme has the same key storage as Asano's method 2 and requires a message length of at most 2r - 1, whereas Asano's schemes require a message length of at most r ((log a) over bar /log n/(r) over barg + 1). Therefore, our scheme is more efficient than the SD scheme and Asano's schemes.