(*Specialization of HMAC256_DRBG_generate_algorithm: no additional input*)
Definition FunGenerate RI (WS: DRBG_functions.DRBG_working_state) n: DRBG_functions.DRBG_generate_algorithm_result :=
           HMAC256_DRBG_functional_prog.HMAC256_DRBG_generate_algorithm RI
                                           WS
                                           n
                                           nil.

Lemma fold_vector_length: forall l m, fold_left (fun (acc : nat) (a : Vector.t bool 256) => (acc + Datatypes.length (Vector.to_list a))%nat) l m = (m + Datatypes.length l * 256)%nat.