According to one embodiment, a device includes first and second data generator, a one-way function processor, and a data output interface. The first data generator generates a second key by encrypting a host constant with a first key in AES operation. The second data generator generates a session key by encrypting a random number with a second key in AES operation. The one-way function processor generates authentication information by processing secret identification information with the session key in one-way function operation. The data output interface outputs the encrypted secret identification information, a family key block, and the authentication information to outside of the device.