An access control scheme based on Chinese remainder theorem and time stamp concept

In this paper we propose a new dynamic access control method for the computer system with frequently inserted, deleted and updated users/files. Our method, based on the concepts of the access control matrix, key-lock-pair, time stamp and Chinese remainder theorem, associates each user with a user key and a user lock and each file with a file key and a file lock. Our method can achieve the following four goals. 1.(1) By a simple modulo operation on the keys and locks of the user and the file, we can reveal the access right of a user to a file. 2.(2) When a user/file is added to the computer system, we only assign a key and a lock to the user/file without affecting the keys and locks of the other users/files in the system. 3.(3) When a user/file is deleted from the computer system, we simply erase the entry of the user/file in the computer system. 4.(4) When the access right of a user to a file is updated, we merely modify the key and lock of the user or the file without affecting the keys and locks of the other users/ files in the system. The main contribution of our method is that the action of inserting, deleting a user/file, or updating the access right of a user to a file can be done by modifying only one key and one lock, which could not be achieved simultaneously before.