def open_len

bend-collections@1.0.0.0 · spec/crypto/chacha20poly1305.bend:54

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

54def 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>>:
55  match short:
56    case True{}: None{}
57    case False{}:
58      +n = Nat.sub(List.length(&2, U32, data), 16n)
59      open_split(key, nonce, aad, CH.prefix(n, data), CH.suffix(n, data))