Sm4.sm4.unstep: def of bend-osdev-legacy-ciphers@0.1.0.0
Import: import bend-osdev-legacy-ciphers@0.1.0.0/sm4.bend as Sm4
Lines 65-69 of bend-osdev-legacy-ciphers@0.1.0.0/sm4.bend: https://jend.leeeet.dev/read.txt?path=bend-osdev-legacy-ciphers@0.1.0.0/sm4.bend&start_line=65&end_line=69

import Base
import bend-osdev-cipher-modes@0.1.0.0/cipher_modes.bend as M
import bend-osdev-legacy-ciphers@0.1.0.0/legacy_ciphers.bend as L

# the round undone
def sm4.unstep(+tab: L.LcTab, rk: U32, s: M.CmBlock) -> M.CmBlock:
  match s:
    case M.CmBlock{+y0, +y1, +y2, y3}:
      M.CmBlock{U32.xor(y3, sm4.t(tab, U32.xor(U32.xor(U32.xor(y0, y1), y2), rk))), y0, y1, y2}

Uses (5):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.xor
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-cipher-modes@0.1.0.0/cipher_modes.bend&name=CmBlock
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-legacy-ciphers@0.1.0.0/legacy_ciphers.bend&name=LcTab
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-legacy-ciphers@0.1.0.0/sm4.bend&name=sm4.t