US Patent 7284133 Information processing unit

An information processing unit and methods therefore which render it more difficult to infer information being processed within an information processing unit by observing the unit's current consumption or electromagnetic radiation. Specifically, the information processing unit preferably encrypts and decrypts data when the data is read from/written to memories within the unit. The encryption/decryption process may include the use of multiple cryptographic keys, permutated data storage locations, randomly generated keys, and permutated data processing steps.