diff --git a/src/pretix/base/models/orders.py b/src/pretix/base/models/orders.py
index 2a963b46d..0b4b26763 100644
--- a/src/pretix/base/models/orders.py
+++ b/src/pretix/base/models/orders.py
@@ -212,7 +212,7 @@ class Order(LockModel, LoggedModel):
         self.delete()
 
     def email_confirm_hash(self):
-        return hashlib.sha256(settings.SECRET_KEY + self.secret.encode()).hexdigest()[:9]
+        return hashlib.sha256(settings.SECRET_KEY.encode() + self.secret.encode()).hexdigest()[:9]
 
     @property
     def fees(self):