diff --git a/test/validate_response.ml b/test/validate_response.ml
index 75777211..e9ee6bd6 100644
--- a/test/validate_response.ml
+++ b/test/validate_response.ml
@@ -1,5 +1,4 @@
 open Syntax
-(*open Crypto*)
 
 let keys content =
   let open Api in
@@ -74,8 +73,65 @@ let keys content =
         }
   in
 
-  (* validate denominations *)
+  let last_issue_date = ref Timestamp.zero in
+  let* () =
+    (* TODO parse CS *)
+    v.denominations
+    |> list_iter
+         (fun
+           (DenomGroup.Rsa
+              RsaDenomGroup.
+                {
+                  denoms;
+                  value;
+                  fee_withdraw;
+                  fee_deposit;
+                  fee_refresh;
+                  fee_refund;
+                })
+         ->
+           let open RsaDenom in
+           denoms
+           |> list_iter
+                (fun
+                  {
+                    rsa_pub;
+                    master_sig;
+                    stamp_start;
+                    stamp_expire_withdraw;
+                    stamp_expire_deposit;
+                    stamp_expire_legal;
+                    lost= _;
+                  }
+                ->
+                  last_issue_date := Timestamp.max !last_issue_date stamp_start;
+                  let denom_hash =
+                    DenominationHash.hash
+                      (Crypto.RsaPublicKey.to_octets rsa_pub)
+                  in
+                  let open Signatures.DenominationKeyValidity in
+                  verify v.master_public_key master_sig
+                    {
+                      R.master= v.master_public_key;
+                      start= stamp_start;
+                      expire_withdraw= stamp_expire_withdraw;
+                      expire_spend= stamp_expire_deposit;
+                      expire_legal= stamp_expire_legal;
+                      value;
+                      fee_withdraw;
+                      fee_deposit;
+                      fee_refresh;
+                      fee_refund;
+                      denom_hash;
+                    }))
+  in
+  let* () =
+    if !last_issue_date = v.list_issue_date then Ok ()
+    else Fmt.error "list_issue_date is wrong"
+  in
+
   (* validate global-fees *)
+
   (* validate list_issue_date *)
   (* validate auditors *)
   Ok ()