diff --git a/lib/parser.js b/lib/parser.js
index <HASH>..<HASH> 100644
--- a/lib/parser.js
+++ b/lib/parser.js
@@ -263,7 +263,7 @@ module.exports = {
       var now = new Date();
       var skew = Math.abs(now.getTime() - date.getTime());
 
-      if ((now.getTime() - date.getTime()) > options.clockSkew * 1000) {
+      if (skew > options.clockSkew * 1000) {
         throw new ExpiredRequestError('clock skew of ' +
                                       (skew / 1000) +
                                       's was greater than ' +
Update lib/parser.js

clock skew was not handled for negative skews (requests from the future)