Patent ID: 8634557

Claim:
A device capable of communicating with an external device via a controller, comprising: a storage area including at least a first area, a second area and a third area, the first area storing first key information (NKey) and unique secret identification information (SecretID), external reading of data from the first area being inhibited at least after the device is shipped, the second area storing index information, and encrypted secret identification information (E-SecretID) generated by encrypting the secret identification information (SecretID), external reading of data from the second area being permitted, the third area storing key management information (FKB) including information generated by encrypting identification key information (FKey), external reading and writing of data from and to the third area being permitted; and an authentication module(authenticator) authenticating the external device, using the first key information (NKey), the index information and the key management information (FKB) stored in the storage area, wherein second key information (HKey) is generated by an AES encryption calculating using the first key information (NKey) read from the first area of the storage area, and first number (HC) received, from the external device; a session key (SKey) is generated by an AES encryption calculating using the second key information (HKey), and second number (RN) received from the external device; one-way conversion calculating is performed on the secret identification information (SecretID), using the session key (SKey), to generate one-way conversion data (Oneway-ID); the encrypted secret identification information (E-SecretID), the key management information (FKB) and the one-way conversion data (Oneway-ID) are output to the external device via the controller; and the index information read from the second area of the storage area is output to the external device, and is used to select outside secret information (HKeyi,j) necessary for an authentication process from an outside secret information set(HKeyi,j(i=1, . . . , m)) stored in the external device.