Chacha20poly1305.open_len: def of bend-collections-laws-crypto@1.0.0.0
Import: import bend-collections-laws-crypto@1.0.0.0/spec/crypto/chacha20poly1305.bend as Chacha20poly1305
Lines 54-59 of bend-collections-laws-crypto@1.0.0.0/spec/crypto/chacha20poly1305.bend: https://jend.leeeet.dev/read.txt?path=bend-collections-laws-crypto@1.0.0.0/spec/crypto/chacha20poly1305.bend&start_line=54&end_line=59

import Base
import bend-collections-laws-crypto@1.0.0.0/spec/crypto/chacha.bend as CH

def open_len(short: Bool, +key: List<&2, U32>, +nonce: List<&2, U32>, +aad: List<&2, U32>, +data: List<&2, U32>) -> Maybe<&2, List<&2, U32>>:
  match short:
    case True{}: None{}
    case False{}:
      +n = Nat.sub(List.length(&2, U32, data), 16n)
      open_split(key, nonce, aad, CH.prefix(n, data), CH.suffix(n, data))

Uses (9):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.length
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Maybe
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.sub
  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/spec/crypto/chacha20poly1305.bend&name=open_split
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/spec/crypto/chacha.bend&name=prefix
  https://jend.leeeet.dev/definition.txt?path=bend-collections-laws-crypto@1.0.0.0/spec/crypto/chacha.bend&name=suffix