Provided is a controller capable of preventing card makers from conducting unauthorized acts. The controller includes: a controller key storage unit configured to hold a controller key that has been embedded by a controller manufacturing device in advance; a decryption unit configured to receive encrypted media key information that has been generated by a key issuance center that is authorized and to decrypt the received encrypted media key by using the controller key, the encrypted key information generated through encryption of key information with use of the controller key; and an encryption unit configured to encrypt the decrypted media key again by using an individual key that is unique to the controller.