def xtsp.blk

bend-osdev-cipher-modes@0.1.0.0 · PROOF.bend:1372

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

1372# one block under one tweak: D(E(p xor t) xor t xor t) xor t == p
1373def xtsp.blk(~K: Data, ~enc: K -> M.CmBlock -> M.CmBlock, ~dec: K -> M.CmBlock -> M.CmBlock, ~inv: @k: K -> @b: M.CmBlock -> {dec(k, enc(k, b)) == b : M.CmBlock}, +k: K, +p: M.CmBlock, +t: M.CmBlock) -> {T.xts.bdec(~K, ~dec, k, T.xts.benc(~K, ~enc, k, p, t), t) == p : M.CmBlock}:
1374  %Equal.sym(M.CmBlock, M.CmBlock.xor(M.CmBlock.xor(enc(k, M.CmBlock.xor(p, t)), t), t), enc(k, M.CmBlock.xor(p, t)), bx.rblock(enc(k, M.CmBlock.xor(p, t)), t)) : {M.CmBlock.xor(dec(k, _), t) == p : M.CmBlock}
1375  %Equal.sym(M.CmBlock, dec(k, enc(k, M.CmBlock.xor(p, t))), M.CmBlock.xor(p, t), inv(k, M.CmBlock.xor(p, t))) : {M.CmBlock.xor(_, t) == p : M.CmBlock}
1376  bx.rblock(p, t)