Definition bitlength (hashed: list int) (data: list byte) : Z :=
   ((Zlength hashed * WORD + Zlength data) * 8)%Z.

(* Specifications: *)
Lemma bitlength_eq: forall hashed data, bitlength hashed data = s256a_len (S256abs hashed data).
Lemma S256abs_recombine: forall a, S256abs (s256a_hashed a) (s256a_data a) = a.
Lemma round_range: forall {A} (a: list A) (N:Z), N > 0 -> 0 <= Zlength a / N * N <= Zlength a.
Lemma CBLOCKz_gt: CBLOCKz > 0.