diff --git a/lib/Horde.php b/lib/Horde.php
index bea99aff..86d44eb3 100644
--- a/lib/Horde.php
+++ b/lib/Horde.php
@@ -183,7 +183,7 @@ public static function signUrl($url, $now = null)
             $url->add(
                 '_h',
                 Horde_Url::uriB64Encode(
-                    hash_hmac('sha1', $url, $conf['secret_key'], true)
+                    hash_hmac('sha1', $url . '=', $conf['secret_key'], true)
                 )
             );
             return $url;
@@ -284,7 +284,7 @@ public static function signQueryString($queryString, $now = null)
         if ($queryString instanceof Horde_Url) {
             $queryString->setRaw(true)->add(['_t' => $now, '_h' => '']);
             $query = parse_url($queryString, PHP_URL_QUERY);
-            $queryString->add('_h', Horde_Url::uriB64Encode(hash_hmac('sha1', $query, $GLOBALS['conf']['secret_key'], true)));
+            $queryString->add('_h', Horde_Url::uriB64Encode(hash_hmac('sha1', $query . '=', $GLOBALS['conf']['secret_key'], true)));
             return $queryString;
         }