diff --git a/lib/validateSignature.js b/lib/validateSignature.js
index b79fb9c..bdd0b5a 100644
--- a/lib/validateSignature.js
+++ b/lib/validateSignature.js
@@ -35,7 +35,7 @@ module.exports = function(xml, cert, certThumbprint) {
     }
   };
 
-  signed.loadSignature(signature.toString());
+  signed.loadSignature(signature);
 
   var valid = signed.checkSignature(xml);