Patent ID: 8539605

Claim:
A data processing device for connecting between a storage device and a controlling device, the data processing device comprising: an encryption unit configured to encrypt data which is received from the controlling device and is to be transmitted to the storage device; a decryption unit configured to decrypt data which is encrypted, is received from the storage device and is to be transmitted to the controlling device; a receiving unit configured to receive a command from the controlling device; a storing unit configured to store reference data for specifying a command which is executable; a determining unit configured to determine whether the command received by the receiving unit is executable based on the reference data stored in the storing unit; an authentication unit configured to execute authentication between the controlling device and the data processing device; and a controlling unit configured to execute the command which is determined to be executable and to control an operation mode of the data processing device so that, before the authentication by the authentication unit is executed, the data processing device operates in an intercept mode in which an access to the storage device from the controlling device is intercepted, and so that, after the authentication by the authentication unit is executed, the data processing device operates in an access mode in which the access to the storage device from the controlling device is permitted; wherein the storing unit stores the reference data for each of the intercept mode and the access mode, and the determining unit determines whether the received command is executable depending on the operation mode of the data processing device.