def checked
import bend-collections-laws-crypto@1.0.0.0/spec/crypto/blake/blake2b.bend as Blake2bimport Base
277def checked(valid: Bool, a: Array<U32>, length: Nat) -> Maybe<&1,Array<U32>>:
278 match valid:
279 case False{}: None{}
280 case True{}: Some{digest(unchecked(a,length))}