Patent ID: 8290159

Claim:
A data recovery method for an apparatus including a first controller board in which a first encryption key is stored in a first secure memory and a second encryption key encrypted with the first encryption key is stored in a first memory, the apparatus further including a storage unit storing data encrypted with the second encryption key, the method comprising: a back-up step in which the second encryption key is decrypted with the first encryption key and the decrypted second encryption key is stored in an external storage device as a backup key; and a restoring step in which, when the first controller board is replaced with a second controller including a second secure memory configured to store a third encryption key different from the first encryption key, and a second memory, the decrypted second encryption key is read from the external storage device, the read second encryption key is encrypted with the third encryption key stored in the second secure memory, and the second encryption key that is read from the external storage device and encrypted with the third encryption key is stored.