Patent ID: 7978857

Claim:
An integrated circuit comprising: an input unit for dividing content into a plurality of blocks and inputting the plurality of blocks; a key generating unit for sequentially generating keys for encrypting one or plural blocks; a content encrypting unit for encrypting the one or plural blocks by using the generated key; a key information generating unit for generating key information for restoring the generated key used for the encrypting by the generated key, wherein the key information includes the generated keys encrypted with a master key peculiar to the integrated circuit; a storage control unit for outputting contents of each of the blocks encrypted by the content encrypting unit and the key information generated by the key information generating unit to an external storage; a restoration control unit for receiving key information stored in the external storage; a key information restoring unit for restoring the generated keys used for the encrypting from the received key information; an output unit for outputting the restored generated keys to an information processing mechanism for decrypting the contents in each block stored in the external storage; and a key information restoration managing unit for managing a restoration state of the generated keys restored by the key information restoring unit and for determining whether an already restored generated key can be updated or not and whether a generated key to be newly restored can be restored or not on the basis of the restoration state of the generated key already restored, wherein the key sequentially generated by the key generating unit is newly generated when a predetermined condition is satisfied, and varies by every one or plural blocks, and wherein when the key information restoration managing unit determines that restoration is not permitted, the key information restoring unit does not restore the generated key which is not permitted to be restored.