Patent ID: 7076668

Claim:
A data usage controlling apparatus that (1) reads a type 1 key from a storage unit and (a) main data, (b) an encrypted type 2 key produced by encrypting a type 2 key using the type 1 key, and (c) encrypted condition information produced by encrypting condition information using the type 2 key from a recording medium, the condition information being for use in judging as to whether usage of the main data is permitted and not used as an encryption key, (2) decrypts the encrypted condition information using the type 2 key, and (3) controls usage of the read main data based on the condition information, the data usage controlling apparatus comprising: first updating means for updating the condition information in accordance with usage of the read main data; generating means for generating a new type 2 key in accordance with the usage of the read main data; first encrypting means for encrypting the updated condition information using the new type 2 key and replacing the encrypted condition information on the recording medium with the encrypted updated condition information; second updating means for updating the type 1 key in the storage unit in accordance with the usage of the read main data; and second encrypting means for encrypting the new type 2 key using the updated type 1 key and replacing the encrypted type 2 key on the recording medium with the encrypted new type 2 key.