Yet another efficient access control for user hierarchy

H.T. Liaw and C.L. Lei (1992) proposed a scheme for determining relationships between users in a hierarchy in information systems. They mentioned that it is very difficult to add extra relationships into all previously proposed schemes. In this paper, we propose an efficient approach to solve this problem. The proposed scheme also has the following advantages. (1) The storage space required in the system is reduced from O(n²) to 0(72). (2) New users and new relationships can be easily inserted into the system