( Sekolah Tinggi Sandi Negara )
Keywords: Strict Avalanche Criterion (SAC),Bit Independence Criterion (BIC),Advanced Encryption Standard(AES),Substitution Box (S-box),Nonlinearity
Since 2001, Advanced Encryption Standard (AES) block cipher has become a standard algorithm and widely used in cryptographic applications. The heart of AES is a nonlinear substitution box (S-box) that generated using Affine transformation. In this paper, we change the original S-box with Whirlpool’s S-box, S1 and S2 Seed’s S-box. After that, we analyze the effect of their usage in AES and compared them to the original. We decide to use these S-boxes due to the similarity dimension with AES’s S-box. The cryptographic properties such as strict avalanche criterion (SAC), bit independence criterion (BIC), XOR table distribution and nonlinearity of theseS-boxes are analyzed in details. According to our experiments, S1 and S2 Seed’s S-box have an error value close to AES’s S-box error value for all tests but not so with Whirlpool’s S-box. We also test the original and modified AES using SAC. The test results showed that they satisfy SAC.