LAWS.authenc_tamper: law of bend-osdev-aead@0.1.0.0
Import: import bend-osdev-aead@0.1.0.0/LAWS.bend as LAWS
Lines 77-93 of bend-osdev-aead@0.1.0.0/LAWS.bend: https://jend.leeeet.dev/read.txt?path=bend-osdev-aead@0.1.0.0/LAWS.bend&start_line=77&end_line=93

import Base
import bend-osdev-bytes@0.1.0.0/bytes.bend as B
import bend-osdev-crypto@0.1.0.0/crypto.bend as Cr
import bend-osdev-aead@0.1.0.0/aead.bend as Ad
import bend-osdev-aead@0.1.0.0/authenc.bend as Au

# a tag of tlen bytes other than the computed one is refused, and the
# cipher never runs
law authenc_tamper:
  for ~KE: Data
  for ~KM: Data
  for ~dec: KE -> B.Octets -> B.Octets -> Result<&2, &2, Cr.CrError, B.Octets>
  for ~mac: KM -> B.Octets -> B.Octets
  for ~input: B.Octets -> B.Octets -> B.Octets -> B.Octets
  for ~tlen: Nat
  for +k: Au.AdAuthencKey<KE, KM>
  for +iv: B.Octets
  for +aad: B.Octets
  for +c: B.Octets
  for +t: B.Octets
  for hl: {B.Octets.len(t) == tlen : Nat}
  for ht: {Ad.AdTag.is_eq(Au.AdAuthenc.tag(~KE, ~KM, ~mac, ~input, ~tlen, k, aad, iv, c), t) == False{} : Bool}
  {Au.AdAuthenc.open(~KE, ~KM, ~dec, ~mac, ~input, ~tlen, k, iv, aad, B.Octets.append(c, t)) == Fail{Cr.CrTagMismatch{}} : Result<&2, &2, Cr.CrError, B.Octets>}

Uses (20):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Equal.sym
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Result
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Result.bind
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Unit
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-aead@0.1.0.0/PROOF.bend&name=split_join
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-aead@0.1.0.0/aead.bend&name=AdSplit
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-aead@0.1.0.0/aead.bend&name=AdTag.is_eq
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-aead@0.1.0.0/aead.bend&name=AdTag.split
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-aead@0.1.0.0/authenc.bend&name=AdAuthenc.open
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-aead@0.1.0.0/authenc.bend&name=AdAuthenc.tag
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-aead@0.1.0.0/authenc.bend&name=AdAuthencKey
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-aead@0.1.0.0/authenc.bend&name=ad.au.check
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-aead@0.1.0.0/authenc.bend&name=ad.au.ke
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-aead@0.1.0.0/authenc.bend&name=ad.au.open.go
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-bytes@0.1.1.0/bytes.bend&name=Octets
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-bytes@0.1.1.0/bytes.bend&name=Octets.append
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-bytes@0.1.1.0/bytes.bend&name=Octets.len
  https://jend.leeeet.dev/definition.txt?path=bend-osdev-crypto@0.1.0.0/crypto.bend&name=CrError