KEY SCHEDULER FOR SELECTIVELY GENERATING ENCRYPTION ROUND KEY AND DECRYPTION ROUND KEY CORRESPONDING TO INITIAL ROUND KEY HAVING VARIABLE KEY LENGTH

摘要

PPROBLEM TO BE SOLVED: To provide a key scheduler for selectively generating an encryption round key and a decryption round key corresponding to an initial round key having a variable key length. PSOLUTION: The key scheduler includes a key storage unit, a key calculating unit, and a key output unit. The key storage unit receives and stores calculation key data or storage key data as input key data in response to load enable signals and a clock signal, and outputs the stored input key data as the storage key data. The key calculating unit calculates the storage key data and outputs the calculation key data as the calculation result in response to calculation control signals. The key output unit selects some of the input key data and the storage key data in response to output control signals, and outputs them as an encryption round key or a decryption round key. PCOPYRIGHT: (C)2005,JPO&NCIPI