--- a/slixmpp/plugins/xep_0078/legacyauth.py
+++ b/slixmpp/plugins/xep_0078/legacyauth.py
@@ -106,7 +106,7 @@ class XEP_0078(BasePlugin):
             stream_id = bytes(self.xmpp.stream_id, encoding='utf-8')
             password = bytes(self.xmpp.password, encoding='utf-8')
 
-            digest = hashlib.sha1(b'%s%s' % (stream_id, password)).hexdigest()
+            digest = hashlib.sha1('%s%s' % (stream_id, password)).hexdigest()
             iq['auth']['digest'] = digest
         else:
             log.warning('Authenticating via jabber:iq:auth Plain.')