diff --git a/sermepa/__init__.py b/sermepa/__init__.py
index 48fdaee..4670d8c 100644
--- a/sermepa/__init__.py
+++ b/sermepa/__init__.py
@@ -280,10 +280,6 @@ def error(message):
             camell = _notification_fields_upper[key]
             data[camell]=data[key]
             del data[key]
-            continue
-
-        if key not in _notification_fields:
-            error("Bad parameter '{}'".format(key))
 
     return data
 
diff --git a/sermepa/sermepa_test.py b/sermepa/sermepa_test.py
index b481db1..ffc823f 100755
--- a/sermepa/sermepa_test.py
+++ b/sermepa/sermepa_test.py
@@ -411,19 +411,19 @@ def test_decodeSignedData_badSignature(self):
         msg = cm.exception.args[0]
         self.assertEqual(msg, 'Bad signature')
 
-    def test_decodeSignedData_badParam(self):
+    def test_decodeSignedData_unexpectedParam(self):
         json_data = '{"Ds_Order":"666", "Bad":"value"}'
         base64_data = base64.urlsafe_b64encode(b(json_data))
         signature = signPayload(self.secret, base64_data, urlsafe=True)
-        with self.assertRaises(SignatureError) as cm:
-            decodeSignedData(
-                self.merchantkey,
-                Ds_MerchantParameters = base64_data,
-                Ds_Signature = signature,
-                Ds_SignatureVersion = self.signatureversion,
-                )
-        msg = cm.exception.args[0]
-        self.assertEqual(msg, "Bad parameter 'Bad'")
+
+        data = decodeSignedData(
+            self.merchantkey,
+            Ds_MerchantParameters=base64_data,
+            Ds_Signature=signature,
+            Ds_SignatureVersion=self.signatureversion,
+        )
+
+        self.assertEqual(data, dict(Ds_Order='666', Bad='value'))
 
     def test_decodeSignedData_upperCaseOrder(self):
         json_data = '{"DS_ORDER":"666"}'