A Low-Cost Key Derivation Scheme for Hierarchy-Based Access

In current content delivery service, contents are usually encrypted for access control mechanism, so several key distribution schemes have been proposed. In this paper, we propose a new key derivation scheme for hierarchy-based access control. We assume that content consumers are listed in digraph structure, and all nodes are assigned seeds(pre-keys) for decryption keys. All decryption keys are generated from initial keys assigned in root nodes, and a decryption key is derived from seeds of an ancestor node only using the one-way hash function. The proposed scheme includes conventional hierarchy-based key derivation schemes and can be implemented with low cost in computation for decryption keys because we do not need exponential calculations.