diff --git a/src/SAML2/HTTPRedirect.php b/src/SAML2/HTTPRedirect.php
index 0854c08d7..bbb04c47f 100644
--- a/src/SAML2/HTTPRedirect.php
+++ b/src/SAML2/HTTPRedirect.php
@@ -222,7 +222,7 @@ public static function validateSignature(array $data, XMLSecurityKey $key)
             $key = SAML2_Utils::castKey($key, $sigAlg);
         }
 
-        if (!$key->verifySignature($query, $signature)) {
+        if ($key->verifySignature($query, $signature) !== 1) {
             throw new Exception('Unable to validate signature on query string.');
         }
     }