Patent ID: 7913094

Claim:
An information reproducing apparatus for reproducing information which is transmitted through a transmission medium or stored in a recording medium, comprising: a secure module, which is a tamper resistant module structure not allowing access to first information from outside, and stores the first information; an insecure memory which allows unauthorized access and tampering of data from outside; and a controller configured for: loading a different decryption unit in the insecure memory every time the decryption unit is loaded, so that the decryption unit decrypts the encryption in a different manner every time the decryption unit is loaded, and executing the decryption unit in the insecure memory for decrypting an encryption applied to encrypted content information by using a predetermined key, wherein: a key supply unit which is implemented in the secure module, supplies the first information as the predetermined key to the decryption unit in the insecure memory for decrypting the encrypted content information; an authentication unit which is implemented in the secure module, supplies second information to the decryption unit in the insecure memory at predetermined time intervals, refers to third information returned from the decryption unit in the insecure memory in response to the second information, and checks authenticity of the decryption unit in the insecure memory based on the third information, where the second information is predetermined; and a key-supply stop unit which is implemented in the secure module, stops supply of the predetermined key by the key supply unit when the authentication unit does not authenticate the decryption unit in the insecure memory.