diff --git a/notebook/static/base/js/utils.js b/notebook/static/base/js/utils.js
index a780b738c..8f54a6384 100644
--- a/notebook/static/base/js/utils.js
+++ b/notebook/static/base/js/utils.js
@@ -208,7 +208,7 @@ define([
          * http://www.ietf.org/rfc/rfc4122.txt
          */
         var s = [];
-        var hexDigits = "0123456789ABCDEF";
+        var hexDigits = "0123456789abcdef";
         for (var i = 0; i < 32; i++) {
             s[i] = hexDigits.substr(Math.floor(Math.random() * 0x10), 1);
         }