Real time block data encryption/decryption processor using Rijndael block cipher and method therefor

摘要

PURPOSE: An apparatus and a method for decrypting block data using a Rijndael algorithm are provided to reduce a period of time for performing an encryption process and a decryption process by sharing encryption module with decryption module and integrating shift operation and replace operation. CONSTITUTION: An apparatus for decrypting block data using a Rijndael algorithm includes an input key adder unit, a round-calculation unit. The input key adder(300) performs an exclusive logical OR operation for block data and input encryption keys. The round calculation unit(302) performs an encryption/decryption process corresponding to one round by using an output of the input key adder and an input encryption key. The round control unit(301) controls the round calculation unit to count the number of rounds and perform repeatedly the encryption/decryption process.