diff --git a/src/crypto/webcrypto-browser.js b/src/crypto/webcrypto-browser.js
index 3848ae2..e55cae5 100644
--- a/src/crypto/webcrypto-browser.js
+++ b/src/crypto/webcrypto-browser.js
@@ -3,12 +3,12 @@
 'use strict'
 
 module.exports = function getWebCrypto () {
-  if (typeof window !== 'undefined') {
+  if (typeof self !== 'undefined') {
     // This is only a shim for interfaces, not for functionality
-    require('webcrypto-shim')(window)
+    require('webcrypto-shim')(self)
 
-    if (window.crypto) {
-      return window.crypto
+    if (self.crypto) {
+      return self.crypto
     }
   }