Definition c := c.Definition C := C.Definition p := p.Definition b := b.Definition B := B.Definition BS: (SHA256.BlockSize * 8)%nat = b.Definition h := sha_h.Definition h_length := sha_h_length.(*  Definition h_v := h_v.
  Definition h_eq := h_eq.*)
  Definition ir: list int := SHA256.init_registers.

Lemma iv_length: length (HMAC_spec_pad.convert ir) = c.