An Improvement of the Design of Integrating Subliminal Channel with Access Control

Recently, Lee and Yang proposed a subliminal scheme which employs an access control in a hierarchy. In their scheme, chief users use a one-way hash function to compute their subordinates’ secret keys with low computation efficiency. And we also find some drawbacks, which are potential loopholes of the security. In this paper, we will show that their scheme suffers inside malicious user attack. And, accordingly, we will present an improved scheme to enhance the security against this flaw.