A system includes at least two buses including a first bus and a second bus, an encryption and decryption system corresponding to each bus, at least one signal processing module corresponding to each bus, and a bus converter coupled between the first bus and the second bus. According to the system provided in embodiments of the present invention, because data transmitted on a bus is encrypted data, even though an attacker obtains bus data by means of a probe attack, it is quite difficult to break a key, and an anti-attack capability of the system can be improved.