Reducing Space for Storing Keys in a Single Key Access Control System

Jan proposed a mechanism that fulfils the requirement of a single key-lock (SKL for short) information protection system. Using Jan’s SKL method, each user is given a key, each file a sequence number, and an operating on the key of a user with the sequence number of a file yields the user’s corresponding access privilege on the file. In Jan’s literature, a formula to compute each user’s key for a given set of assigned sequence numbers and a set of corresponding access privileges is also provided. However, different assignments of sequence numbers to the secured files will yield different keys. In this paper, an efficient way to assign a set of sequence numbers to the set of files such that the maximal key value is minimized is presented.