Abstract. We study the problem of broadcasting confidential information to a collection of n devices while providing the ability to revoke an arbitrary subset of those devices (and tolerating collusion among the revoked devices). In this paper, we restrict our attention to low-memory devices, that is, devices that can store at most O(log n) keys. We consider solutions for both zero-state and low-state cases, where such devices are organized in a tree structure T . We allow the group controller to encrypt broadcasts to any subtree of T , even if the tree is based on an multi-way organizational chart or a severely unbalanced multicast tree.
Stateless and low-state BE in low-memory devices was considered in REF .
Efficient tree-based revocation in groups of low-state devices
In Proceedings of Crypto ’04, volume 2204 of LNCS
Computer Science