def tr.xcrypt

bend-osdev-cipher-modes@0.1.0.0 · PROOF.bend:1223

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/ccm.bend as CC

1223def tr.xcrypt(~K: Data, ~enc: K -> M.CmBlock -> M.CmBlock, +k: K, +a0: M.CmBlock, s: M.CmSplit) -> {CC.ccm.xcrypt(~K, ~enc, k, a0, s) == CC.ccm.xcrypt.fast(~K, ~enc, k, a0, s) : List<&2, U32>}:
1224  match s:
1225    case M.CmSplit{+bs, +tail}:
1226      %tr.len_eq(bs) : {CC.ccm.xcrypt(~K, ~enc, k, a0, M.CmSplit{bs, tail}) == M.cm.join_onto.fast(CC.ccm.ctrb.fast(~K, ~enc, k, bs, a0, 1), M.cm.xor_bytes(tail, M.cm.bytes_of(enc(k, CC.ccm.ai(a0, U32.add(1, U32.from_nat(_))))))) : List<&2, U32>}
1227      %tr.ctrb_eq(~K, ~enc, k, bs, a0, 1) : {CC.ccm.xcrypt(~K, ~enc, k, a0, M.CmSplit{bs, tail}) == M.cm.join_onto.fast(_, M.cm.xor_bytes(tail, M.cm.bytes_of(enc(k, CC.ccm.ai(a0, U32.add(1, U32.from_nat(List.length(&2, M.CmBlock, bs)))))))) : List<&2, U32>}
1228      %tr.join_eq(CC.ccm.ctrb(~K, ~enc, k, bs, a0, 1), M.cm.xor_bytes(tail, M.cm.bytes_of(enc(k, CC.ccm.ai(a0, U32.add(1, U32.from_nat(List.length(&2, M.CmBlock, bs)))))))) : {CC.ccm.xcrypt(~K, ~enc, k, a0, M.CmSplit{bs, tail}) == _ : List<&2, U32>}
1229      {==}