unfold cAU.Adv_WCR, cAU.Adv_WCR_G.
comp_skip.
unfold Y.
eapply comp_spec_impl_le.
simpl.
inline_first.
comp_skip.
eapply (@oc_comp_spec_eq _ _ _ _ _ _ _ _ _ _ _ _ _ _ (fun a b => fst b = a)).
trivial.
intuition.
subst.
unfold cAU.WCR_Oracle.
inline_first.
comp_simp.
inline_first.
comp_simp.
simpl.
eapply comp_spec_ret.
intuition.
simpl in *.
intuition.
destruct b2.
simpl in *.
subst.
comp_simp.
simpl.
comp_simp.
inline_first.
comp_simp.
eapply comp_spec_ret.
intuition.
unfold h_star_pad in *.
case_eq (eqb a b1); intuition;
rewrite H3 in H2;
simpl in *.
discriminate.
apply eqbBvector_sound in H2.
unfold HMAC_spec.h_star_pad, HMAC_spec.app_fpad in *.
eapply Vector_append_inj_first in H2.
unfold h_star, NMAC_to_HMAC.h_star.
rewrite H2.
eapply eqbBvector_complete.
Qed.
End h_star_WCR.
Definition HMAC := HMAC h iv splitAndPad fpad opad ipad.
Definition GHMAC := GHMAC h iv fpad opad ipad.
Variable A : OracleComp Message (Bvector c) bool.
Hypothesis A_wf : well_formed_oc A.
Definition A_GHMAC : OracleComp (list (Bvector b)) (Bvector c) bool :=
[b, _] <--$2 OC_Run _ _ _ A
(fun _ q =>
ls <- splitAndPad q;
r <--$ OC_Query _ ls;
$ ret (r, tt)) tt;
$ ret b.

(* Specifications: *)
Theorem GHMAC_to_HMAC :
PRF_Advantage (Rnd b) (Rnd c) HMAC _ _ A ==
PRF_Advantage (Rnd b) (Rnd c) GHMAC _ _ A_GHMAC.