According to one embodiment, a device includes a first memory area to store a first key. A second memory area stores encrypted secret identification (ID) information generated from secret ID information with a family key. A third memory area stores a family key block including data generated from the family key with an ID key. An authentication module performs authentication. A second key is generated from a first number with the first key, a session key is generated from a random number with the second key, and authentication information is generated from the secret ID information with the session key. The encrypted secret ID information, family key block and the authentication information is output.