def xts.dsteal.go

bend-osdev-cipher-modes@0.1.0.0 · xts.bend:133

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

133# the plaintext of the last whole ciphertext block c and the tail
134def xts.dsteal.go(~K: Data, ~dec: K -> M.CmBlock -> M.CmBlock, partial: Bool, +k: K, c: M.CmBlock, +tail: List<&2, U32>, +t: M.CmBlock) -> List<&2, U32>:
135  match partial:
136    case False{}:
137      M.cm.bytes_of(xts.bdec(~K, ~dec, k, c, t))
138    case True{}:
139      +pp = M.cm.bytes_of(xts.bdec(~K, ~dec, k, c, Xts.mul_alpha(t)))
140      M.cm.bytes_onto(xts.bdec(~K, ~dec, k, M.cm.block_of(B.append(tail, B.drop(B.len(tail), pp))), t), B.take(B.len(tail), pp))