diff --git a/lib/index.js b/lib/index.js
index 9b303a6..75d2d35 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -65,6 +65,8 @@ function parseHeader(headers) {
   return raw;
 }
 
+const crypto = require('crypto');
+
 function buildHash(url, args) {
   var json = {}
   if (args) {
@@ -95,7 +97,12 @@ function buildFilenamePrefix(url, args, hash) {
   url = escape(url).replace(/\//g, '_')
   var method = args.method || 'GET'
   method = method.toUpperCase()
-  return url + '_' + method + '_' + hash
+
+  var namehash = crypto.createHash('sha256');
+  code = namehash.update(url);
+  digest = namehash.digest("base64").replace(/[^A-Za-z]/g, "");
+
+  return digest; // + '_' + method + '_' + hash
 }
 
 function buildOptionsFilename(url, args, hash) {