def cmblock_xx

bend-osdev-crypto@0.1.0.0 · PROOF.bend:255

import Base
import bend-osdev-cipher-modes@0.1.0.0/cipher_modes.bend as M
import bend-osdev-crypto@0.1.0.0/inst_cm.bend as CM

255def cmblock_xx(s: M.CmBlock, k: M.CmBlock) -> {s == CM.CrBlk128.xor(CM.CrBlk128.xor(s, k), k) : M.CmBlock}:
256  match s k:
257    case M.CmBlock{+a0, +a1, +a2, +a3} M.CmBlock{+b0, +b1, +b2, +b3}:
258      %u32_xx(a0, b0) : {M.CmBlock{a0, a1, a2, a3} == M.CmBlock{_, U32.xor(U32.xor(a1, b1), b1), U32.xor(U32.xor(a2, b2), b2), U32.xor(U32.xor(a3, b3), b3)} : M.CmBlock}
259      %u32_xx(a1, b1) : {M.CmBlock{a0, a1, a2, a3} == M.CmBlock{a0, _, U32.xor(U32.xor(a2, b2), b2), U32.xor(U32.xor(a3, b3), b3)} : M.CmBlock}
260      %u32_xx(a2, b2) : {M.CmBlock{a0, a1, a2, a3} == M.CmBlock{a0, a1, _, U32.xor(U32.xor(a3, b3), b3)} : M.CmBlock}
261      %u32_xx(a3, b3) : {M.CmBlock{a0, a1, a2, a3} == M.CmBlock{a0, a1, a2, _} : M.CmBlock}
262      {==}