diff --git a/src/jwt-token.js b/src/jwt-token.js
index eb7c213..be404a8 100644
--- a/src/jwt-token.js
+++ b/src/jwt-token.js
@@ -1,6 +1,6 @@
 var jwt = {};
 
-var JWTInternals = (function() {
+var JWTInternals = (function(window) {
 
   // convert a base64url string to hex
   var b64urlmap="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
@@ -89,30 +89,30 @@ var JWTInternals = (function() {
     this.key = sjcl.codec.utf8String.toBits(key);
   }
 
-  HMACAlgorithm.prototype = 
+  HMACAlgorithm.prototype =
   {
     update: function _update(data)
     {
       this.data = data;
     },
-    
+
     finalize: function _finalize()
     {
     },
-    
+
     sign: function _sign()
     {
       var hmac = new sjcl.misc.hmac(this.key, this.hash);
       var result = hmac.encrypt(this.data);
       return base64urlencode(window.atob(sjcl.codec.base64.fromBits(result)));
     },
-    
+
     verify: function _verify(sig)
     {
       var hmac = new sjcl.misc.hmac(this.key, this.hash);
       var result = hmac.encrypt(this.data);
-      
-      return base64urlencode(window.atob(sjcl.codec.base64.fromBits(result))) == sig; 
+
+      return base64urlencode(window.atob(sjcl.codec.base64.fromBits(result))) == sig;
     }
   }
 
@@ -123,7 +123,7 @@ var JWTInternals = (function() {
     } else if (hash == "sha256") {
       this.hash = "sha256";
     } else {
-      throw new NoSuchAlgorithmException("JWT algorithm: " + hash);  
+      throw new NoSuchAlgorithmException("JWT algorithm: " + hash);
     }
     this.keyPEM = keyPEM;
   }
@@ -135,7 +135,7 @@ var JWTInternals = (function() {
     },
     finalize: function _finalize()
     {
-    
+
     },
     sign: function _sign()
     {
@@ -225,7 +225,7 @@ var JWTInternals = (function() {
       var signatureValue = algorithm.sign();
       return algBytes + "." + jsonBytes + "." + signatureValue;
     },
-    
+
     verify: function _verify(key)
     {
       var header = jsonObj(this.pkAlgorithm);
@@ -236,9 +236,9 @@ var JWTInternals = (function() {
       return algorithm.verify(this.cryptoSegment);
     }
   }
-  
+
   jwt.WebToken = WebToken;
   jwt.WebTokenParser = WebTokenParser;
   jwt.base64urlencode = base64urlencode;
   jwt.base64urldecode = base64urldecode;
-})();
\ No newline at end of file
+})(this);
\ No newline at end of file