(*Require Import FCF.HMAC_DRBG_definitions_only.*)

Lemma HMAC_DRBG_generate_helper_Z_equation':
forall (HMAC : list byte -> list byte -> list byte) (key v : list byte) (requested_number_of_bytes : Z),
0 < requested_number_of_bytes ->
HMAC_DRBG_generate_helper_Z HMAC key v requested_number_of_bytes =
let (v0, rest) := HMAC_DRBG_generate_helper_Z HMAC key v (requested_number_of_bytes - Z.of_nat 32) in
(HMAC v0 key, rest ++ HMAC v0 key).