A practical and dynamic key management scheme for a user hierarchy

INTRODUCTIONThe access control problem in an arbitrary par-tially ordered user hierarchy is defined below. In an organization, the users and their authorized data are organized into a group of disjoint sets of security classes, and each user is assigned to a certain security class called his security clearance. Let C1, C2, …, Cn, n∈ù, be n disjoint security classes and ‘≤’ be a binary partial-order relation over the set C={C1, C2, …, Cn}. For the set (C, ≤), Cj≤Ci (i, j∈ù) …

A practical and dynamic key management scheme for a user hierarchy

In this paper, we proposed a practical and dynamic key management scheme based on the Rabin public key system and a set of matrices with canonical matrix multiplication to solve the access control problem in an arbitrary partially ordered user hierarchy. The advantage is in ensuring that the security class in the higher level can derive any of its successor’s secret keys directly and efficiently and show it is dynamic while a new security class is added into or a class is removed from the hierarchy. Even the ex-member problem can be solved efficiently. Moreover, any user can freely change its own key for some security reasons.