Assigning Keys in a Hierarchy

Access control problem is a vital research topic which has been widely discussed in many years. Recently, several schemes for access control have been proposed. However, most schemes own some flaws in different perspectives. In this paper, we propose a secure key assignment scheme by utilizing the discrete logarithm, Diffie-Hellman key exchange, and a secure one-way hash function. In our proposed scheme, not only the cost of renewing and revoking the keys can be reduced, but also the public information is verifiable for some particular hierarchies.