Dynamic Access Control in a Hierarchy with Constant Key Derivation Cost

Abstract

While providing access control in a hierarchical access structure, a partially ordered set of security classes can be used to depict an access hierarchy. Data accessible to descendants of a particular security class should also be accessible to the users of that security class. Towards this, an access control scheme is proposed for providing dynamic hierarchical access control. In the proposed solution, the storage at the users is constant. The public key storage is equal to the size of the hierarchy. Also, deriving the decryption key of a descendant class involves constant cost at the users in the security class.