Controller for data storage device, data storage device, and control method thereof

A data storage device comprising:

• a storage module configured to store data encrypted with a first key;
• an input and output module configured to manage data input and output between the storage module and a host;
• a plurality of encryption and decryption modules configured to be switched to function as an encryptor or a decryptor;
• and
• a connector configured to change connection between the encryption and decryption modules and the host,
• wherein, when encrypted data is backed up, one of the encryption and decryption modules on a side of the storage module is configured to function as a decryptor, while one of the encryption and decryption modules on a side of the host is configured to function as an encryptor,
• the decryptor, the encryptor, and the host are connected in series, and
• the encrypted data is decrypted by the decryptor with the first key and is then encrypted by the encryptor with a second key to be output from the input and output module to the host.

A control method applied to a data storage device comprising a storage module configured to store data encrypted with a first key, an input and output module configured to manage data input and output between the storage module and a host, a plurality of encryption and decryption modules configured to be switched to function as an encryptor or a decryptor, and a connector configured to change connection between the encryption and decryption modules and the host, the control method comprising:

• when first encrypted data is backed up,
• switching one of the encryption and decryption modules on a side of the storage module to function as a decryptor;
• switching one of the encryption and decryption modules on a side of the host to function as an encryptor;
• connecting the decryptor, the encryptor, and the host in series;
• decrypting the first encrypted data by the decryptor with the first key to obtain first decrypted data;
• encrypting the first decrypted data by the encryptor with a second key to obtain second encrypted data;
• and
• outputting the second encrypted data encrypted with the second key from the input and output module to the host.