S-boxes with good cryptographic properties can be produced by algebraically reverse mapping. However, S-boxes with good cryptographic properties or even the same cryptographic properties can be produced using some power functions. For example, we can obtain such S-boxes with 4-bit input 4-bit output x x?, x x11 and xx13 power maps. Question: Design a 4-bit input 4-bit output S-box with xx13 power mapping method. (Use irreducible polynomial: x4 + x + 1) S-boxes with good cryptographic properties can be produced by algebraically reverse mapping. However, S-boxes with good cryptographic properties or even the same cryptographic properties can be produced using some power functions. For example, we can obtain such S-boxes with 4-bit input 4-bit output x x?, x x11 and xx13 power maps. Question: Design a 4-bit input 4-bit output S-box with xx13 power mapping method. (Use irreducible polynomial: x4 + x + 1)