DYNAMIC ACCESS-CONTROL SCHEME BASED ON THE CHINESE REMAINDER THEOREM

This paper presents a cryptographic key assignment scheme for solving the access control problem in a partially ordered user hierarchy. Based on the Chinese remainder theorem, each user is assigned a secret key, a deriving key, and the corresponding public parameters. Any user with higher security clearance can directly derive his successor's deriving key by using his own secret key and his successor's public parameters. Then the user Elses the deriving key to obtain his successor's encryption key. The dynamic access control problems, such as adding/deleting users, adding/deleting relationships, and changing secret/encryption keys, are considered. We also show that the proposed scheme can withstand the attack of collusion.