A device authentication module and an encryption module can be connected via a dynamic link in a CE device.A random number is generated in an authentication server (5). The device authentication module (7) combines a pass-phrase and this random number to generate a digest, and transmits this and a device ID to the encryption module (8). The encryption module encrypts a communication pathway and transmits these items of information to the authentication server (5). The authentication server (5) searches for the pass-phrase based on the device ID and combines this and the generated random number to generate a digest. This digest is compared with the digest received from the encryption module (8) for device authentication. The encryption module (8) receives from the device authentication module (7) not the pass-phrase but a digest, and therefore can be connected via a dynamic link instead of a static link.