Abstract: Access control system has always been an important part of access control system ,and Keeloq rolling code technology has a wide range of applications in intelligent access control systems,wireless door locks and other fields.This paper analyzed the encryption and decryption principle of keeloq algorithm and its application in the key code of the access control system.Summarizing some problems of single keeloq algorithm and multiple keeloq algorithm,this paper provided a kind of scheme called dual keeloq algorithm to improve its security.The dual keeloq algorithm is not a simple secondary keeloq algorithm for a key code encryption,it’s another keeloq algorithm encryption of the important field of key code on the basis of single keeloq algorithm encryption.The required information and the code length are different in the two encryption.This encryption method increases the complexity of key code.At the same time,compared to multiple keeloq encryption,it reduces the overhead of system calculation in the key code encryption and decryption process.

Key words: Intelligent access control system, Keeloq algorithm, Password attack, System security