def sp.lt7

bend-osdev-legacy-ciphers@0.1.0.0 · serpent.bend:200

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

200# X2 = X2 xor X3 xor (X1 << 7) (its own inverse)
201def sp.lt7(s: M.CmBlock) -> M.CmBlock:
202  match s:
203    case M.CmBlock{x0, +x1, x2, +x3}:
204      M.CmBlock{x0, x1, U32.xor(x2, U32.xor(x3, U32.shln(x1, 7n))), x3}