Encryption/decryption device, communication controller, and electronic instrument

An encryption/decryption device which performs encryption or decryption processing for divided data of first and second content data, the encryption/decryption device comprising:

• a storage section which stores the divided data as input data and stores output data obtained by subjecting the input data to encryption or decryption processing;
• a first encryption/decryption processing section which performs first encryption processing or first decryption processing for the divided data in an operation mode of a block cipher method using data in a block other than a block under processing;
• a second encryption/decryption processing section which performs second encryption processing or second decryption processing for the divided data in an operation mode of a block cipher method using data in a block other than a block under processing;
• and
• an intermediate value storage section which stores a block-unit processing result or an input value of the first and second encryption/decryption processing section in content units,
• wherein the storage section stores decrypted data obtained by causing one of the first and second encryption/decryption processing sections to perform the first or second decryption processing for the input data;
• wherein the storage section stores data obtained by causing the other of the first and second encryption/decryption processing sections to perform the first or second encryption processing for the decrypted data after the first or second encryption processing as the output data;
• wherein the intermediate value storage section stores the processing result or the input value of the encryption or decryption processing performed by at least one of the first and second encryption/decryption processing sections for one of the divided data of the second content data as the input data;
• and
• wherein the processing result or the input value of the first or second encryption/decryption processing section for the Kth (K is a natural number) divided data of the first content data is read from the intermediate value storage section, and at least one of the first and second encryption/decryption processing sections performs the encryption or decryption processing for the (K+1)th divided data of the first content data as the input data by using the processing result or the input value.

An encryption/decryption device which performs encryption or decryption processing for divided data of first and second content data, the encryption/decryption device comprising:

• a first storage section which is accessible from outside of the encryption/decryption device and stores the divided data as input data;
• a first encryption/decryption processing section which performs first encryption processing or first decryption processing for the divided data in an operation mode of a block cipher method using data in a block other than a block under processing;
• a second encryption/decryption processing section which performs second encryption processing or second decryption processing for the divided data in an operation mode of a block cipher method using data in a block other than a block under processing;
• a second storage section which is inaccessible from outside of the encryption/decryption device and stores decrypted data obtained by subjecting the input data to the first or second decryption processing;
• a third storage section which is accessible from outside of the encryption/decryption device and stores output data obtained by subjecting the input data to the encryption or decryption processing;
• and
• an intermediate value storage section which stores a block-unit processing result or an input value of the encryption/decryption processing section in content units,
• wherein the second storage section stores decrypted data obtained by causing one of the first and second encryption/decryption processing sections to perform the first or second decryption processing for the input data;
• wherein the third storage section stores data obtained by causing the other of the first and second encryption/decryption processing sections to perform the first or second encryption processing for the decrypted data after the first or second encryption processing as the output data;
• wherein the intermediate value storage section stores the processing result or the input value of the encryption or decryption processing performed by at least one of the first and second encryption/decryption processing sections for one of the divided data of the second content data as the input data;
• and
• wherein the processing result or the input value of the first or second encryption/decryption processing section for the Kth (K is a natural number) divided data of the first content data is read from the intermediate value storage section, and at least one of the first and second encryption/decryption processing sections performs the encryption or decryption processing for the (K+1)th divided data of the first content data as the input data by using the processing result or the input value.