Improvement on Short-block Encryption Technology Based on AES

This paper introduces the short-block encryption algorithm based on AES,studies the S-box of the algorithm,and points out that the size of S-box has great influence on encryption performance.The new decimal S-box is constructed by taking multiplicative inverse and applying affine transformation,and its size is 10 times of the original one.And the new S-box is applied in the short-block encryption simulation system,and it shows that the new S-box strengthens the resistance of the algorithm against attack and improves the security of the encryption algorithm.Experiments and simulation indicate that the new S-box improves all the diffusion rate,during which the key to cipher in encryption process increases by 25 percent.