Patent ID: 7925895

Claim:
A data management apparatus comprising: a removable storage device; a nonvolatile memory which is configured and operable to save a first conversion key; a first encrypting device having a second conversion key, the first encrypting device being configured and operable to encrypt the first conversion key by the second conversion key, and configured and operable to convert the first conversion key into a third conversion key, the third conversion key being the encrypted first conversion key; a first writing device which is configured and operable to write the third conversion key into the storage device; a second encrypting device having a fourth conversion key which is different from the second conversion key, the fourth conversion key being a unique key to the data management apparatus, the second encrypting device being configured and operable to encrypt the third conversion key by the fourth conversion key and configured and operable to convert the third conversion key into a fifth conversion key, the fifth conversion key being the encrypted third conversion key; a datum encrypting device which is configured and operable to convert a datum to be saved in the storage device into an encrypted datum by the fifth conversion key; a datum writing device which is configured and operable to write the encrypted datum into the storage device; a datum reading device which is configured and operable to read the encrypted datum from the storage device; a datum decrypting device which is configured and operable to decrypt the encrypted datum by the fifth conversion key; and a deleting device which is configured and operable to delete the fifth conversion key after encryption by the datum encrypting device and after decryption by the datum decrypting device.