Laws.involution: law of bend-collections-laws-crypto@1.0.0.0
Import: import bend-collections-laws-crypto@1.0.0.0/proofs/crypto/chacha/laws.bend as Laws
Lines 117-124 of bend-collections-laws-crypto@1.0.0.0/proofs/crypto/chacha/laws.bend: https://jend.leeeet.dev/read.txt?path=bend-collections-laws-crypto@1.0.0.0/proofs/crypto/chacha/laws.bend&start_line=117&end_line=124

import Base
import bend-collections-laws-crypto@1.0.0.0/src/crypto/chacha/chacha20.bend as I

# Decryption is encryption: applying the cipher twice is the identity.
law involution:
  for +r: Nat
  for +key: List<&2, U32>
  for +counter: U32
  for +nonce: List<&2, U32>
  for +plaintext: List<&2, U32>
  {I.encrypt_rounds(r, key, counter, nonce, I.encrypt_rounds(r, key, counter, nonce, plaintext)) == plaintext : List<&2, U32>}

Uses (9):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Equal.cong
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Equal.trans
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/proofs/crypto/chacha/involution.bend&name=involution
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/proofs/crypto/chacha/stream.bend&name=encrypt_correct
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/spec/crypto/chacha.bend&name=encrypt_rounds
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/src/crypto/chacha/chacha20.bend&name=encrypt_rounds