diff --git a/lib/elliptic/utils.js b/lib/elliptic/utils.js
index 568a3e2..b3ef2d2 100644
--- a/lib/elliptic/utils.js
+++ b/lib/elliptic/utils.js
@@ -14,14 +14,15 @@ utils.encode = minUtils.encode;
 // Represent num in a w-NAF form
 function getNAF(num, w, bits) {
   var naf = new Array(Math.max(num.bitLength(), bits) + 1);
-  for (var i = 0; i < naf.length; i += 1) {
+  var i;
+  for (i = 0; i < naf.length; i += 1) {
     naf[i] = 0;
   }
 
   var ws = 1 << (w + 1);
   var k = num.clone();
 
-  for (var i = 0; i < naf.length; i++) {
+  for (i = 0; i < naf.length; i++) {
     var z;
     var mod = k.andln(ws - 1);
     if (k.isOdd()) {