The AES S-box

1 · John Cook · May 25, 2019, 4:17 p.m.
The AES (Advanced Encryption Standard) algorithm takes in blocks of 128 or more bits [1] and applies a sequence of substitutions and permutations. The substitutions employ an “S-box”, named the Rijndael S-box after its designers [2], an invertible nonlinear transformation that works on 8 bits at a time. There are 256 = 16 × 16 […]...