Design of an improved method of AES S-box
MA Hong-bo · Journal of Central South University(Science and Technology) · 2007
S-box is the unique nonlinear operation for advanced encryption standard(AES) and affects the capability of the algorithm.For S-box,the period of affine transformed pair is 4,the period of iterative-output is less than 88 and algebraic expression has only 9 items.Based on these characteristics,an improved S-box was constructed,with period of affine transformed pair as 16,period of iterative-output as 256 and algebraic expression of improved S-box and InvS-box as 252 items and 254 items respectively.The improved S-box was compared with AES S-box in 10 algebraic properties,such as the balance,strict avalanche criterion,non-linear degree,resistance against the XSL attack,etc.The results suggest that the improved S-box has better algebraic characteristics and stronger resistance against algebraic attack.