Towards Time-Bound Hierarchical Key Assignment for Secure Data Access Control

Abstract

Time-bound hierarchical key assignment (TBHKA) scheme is a cryptographic method to assign encryption keys to a set of security classes in a partially ordered hierarchy. Only the authorized subscriber who holds the corresponding key can access the encrypted resources. In 2005, Yeh proposed a RSA-based TBHKA scheme which is suitable for discrete time period. However, it had been proved insecure against colluding attacks. Up to now, no such TBHKA schemes were proposed. In this paper, we fuse pairing-based cryptography and RSA key construction to propose a secure TBHKA scheme. In particular, our scheme is suitable for discrete time period. The security analysis is demonstrated that our scheme is secure against outsider and insider attacks (including colluding attacks). Finally, the performance analysis and comparisons are given to demonstrate our advantage.