AES Avalanche Effect: SubBytes, ShiftRows & MixColumns

Symmetric-key block ciphers like AES scramble data through repeated rounds of substitution and permutation until the ciphertext looks statistically indistinguishable from noise. This simulator renders two live 4×4 AES-128 state matrices as 3D blocks — one for a plaintext, one for the same plaintext with a single bit flipped — and steps both through the real SubBytes, ShiftRows, MixColumns and AddRoundKey transformations under an identical round-key schedule. A live Hamming-distance readout and diffusion bar show the avalanche effect in action: a one-bit input difference explodes into roughly half of all 128 output bits differing after just a few rounds, which is exactly the diffusion property that makes brute-force pattern analysis of AES ciphertext infeasible.