diff --git a/eopayment/ogone.py b/eopayment/ogone.py
index dc304b3..9d759ef 100644
--- a/eopayment/ogone.py
+++ b/eopayment/ogone.py
@@ -496,7 +496,7 @@ class Payment(PaymentCommon):
         values = [u'%s=%s' % (a, b) for a, b in values if a in keep and b]
         tosign = key.join(values)
         tosign += key
-        tosign = force_byte(tosign)
+        tosign = force_byte(tosign, encoding='iso-8859-1')
         hashing = getattr(hashlib, algo)
         return hashing(tosign).hexdigest().upper()
 
diff --git a/tests/test_ogone.py b/tests/test_ogone.py
index 0aefe25..c8624a9 100644
--- a/tests/test_ogone.py
+++ b/tests/test_ogone.py
@@ -79,7 +79,7 @@ class OgoneTests(TestCase):
                 'cn': u'Usér', 'ncerror': u'0',
                 'trxdate': u'10/24/16', 'acceptance': u'test123',
                 'currency': u'eur', 'amount': u'7.5',
-                'shasign': u'3EE0CF69B5A8514962C9CF8A545861F0CA1C6891'}
+                'shasign': u'CA4B3C2767B5EFAB33B9122A5D4CF6F27747303D'}
         # uniformize to utf-8 first
         for k in data:
             data[k] = eopayment.common.force_byte(data[k])
@@ -96,7 +96,7 @@ class OgoneTests(TestCase):
             '&CARDNO=XXXXXXXXXXXX9999&ED=0118'
             '&CN=Miha%EF+Serghe%EF&TRXDATE=10%2F24%2F16'
             '&PAYID=3011228911&NCERROR=0&BRAND=MasterCard'
-            '&IP=80%2E12%2E92%2E47&SHASIGN=435D5E36E1F4B17739C1054FFD204218E65C15AB'
+            '&IP=80%2E12%2E92%2E47&SHASIGN=C429BE892FACFBFCE5E2CC809B102D866DD3D48C'
         )
         response = ogone_backend.response(backend_response)
         assert response.signed
@@ -121,7 +121,7 @@ class OgoneTests(TestCase):
             'pm': 'bank transfer',
             'currency': u'eur',
             'amount': u'7.5',
-            'shasign': u'0E35F687ACBEAA6CA769E0ADDBD0863EB6C1678A'
+            'shasign': u'944CBD1E010BA4945415AE4B16CC40FD533F6CE2',
         }
         # uniformize to utf-8 first
         for k in data: