Storage device, storage system, and authentication method

A storage system that includes a storage device having a nonvolatile semiconductor memory to store user data and connectable to arbitrary host devices in a detachable manner and an authorized host device having connection authority with respect to the storage device, among the arbitrary host devices,

• wherein the storage device includes
• an authentication information storage unit that previously stores first apparatus authentication information to authenticate an authorized host device having connection authority, among the arbitrary host devices, and first user authentication information to authenticate an authorized user who uses the authorized host device,
• an apparatus authenticating unit that executes apparatus authentication on the basis of second apparatus authentication information received from a newly connected current host device and the first apparatus authentication information in the authentication information storage unit,
• a user data invalidating unit that executes an invalidation process to make user data stored in the nonvolatile semiconductor memory not read, when the apparatus authentication is failed,
• a user authenticating unit that executes user authentication on the basis of the second user authentication information received from the current host device and the first user authentication information in the authentication information storage unit, after the apparatus authentication, and
• a data read unit that outputs the user data stored in the nonvolatile semiconductor memory to the current host device, on the basis of a read request received from the current host device, when the user authentication is succeeded, and
• the authorized host device includes
• an apparatus authentication information storage unit that stores the second apparatus authentication information,
• an apparatus authentication information transmitting unit that transmits the second apparatus authentication information in the apparatus authentication information storage unit to the storage device, according to a predetermined authentication sequence of the apparatus authentication executed by the apparatus authenticating unit, when the storage device is connected,
• a user authentication information receiving unit that receives an input of the second user authentication information, according to an operation from a user,
• a user authentication information transmitting unit that transmits the received second user authentication information to the storage device,
• a read request receiving unit that receives an input of a read request, according to an operation from the user, and
• a read request transmitting unit that transmits the received read request to the storage device.

An authentication method in a storage device that has a nonvolatile semiconductor memory to store user data and is connectable to arbitrary host devices in a detachable manner, the authentication method comprising:

• previously storing first apparatus authentication information to authenticate an authorized host device having connection authority, among the arbitrary host devices, and first user authentication information to authenticate an authorized user who uses the authorized host device in an authentication information storage unit;
• executing apparatus authentication on the basis of second apparatus authentication information received from a newly connected current host device and the first apparatus authentication information in the authentication information storage unit;
• executing an invalidation process to make user data stored in the nonvolatile semiconductor memory not read, when the apparatus authentication is failed;
• executing user authentication on the basis of the second user authentication information received from the current host device and the first user authentication information in the authentication information storage unit, after the apparatus authentication;
• and
• outputting the user data stored in the nonvolatile semiconductor memory to the current host device, on the basis of a read request received from the current host device, when the user authentication is succeeded.