SYMMETRIC KEY BLOCK CIPHER ALGORITHM DESIGN METHOD WITH NO OPERATION BETWEEN KEY AND PLAINTEXT

摘要

PURPOSE: A method for designing a symmetric key block cipher algorithm without calculation between a key and a plaintext is provided to obtain a high degree of encryption by varying an executing routine of an algorithm according to key values and by not performing a calculation process between a round key and a round block. CONSTITUTION: An input process is performed to receive a secret key corresponding to a size of 8 bitsxr(r is a positive integer) and a plaintext corresponding to a size of a multiple of 8(S10). Round keys of r number are generated by using the secret key according to a predetermined key scheduling algorithm(S12). The plaintext is encoded by performing repeatedly a round calculation process by using a bijective function selected according to the round keys of r number(S14). An output process is performed to output a cipher text generated from an encryption process(S16).