diff --git a/src/crypto-browser.js b/src/crypto-browser.js
deleted file mode 100644
index 9035e8ba..00000000
--- a/src/crypto-browser.js
+++ /dev/null
@@ -1,68 +0,0 @@
-'use strict'
-
-const SHA3 = require('browserify-sha3')
-const nodeify = require('nodeify')
-
-const webCrypto = getWebCrypto()
-
-function getWebCrypto () {
-  if (typeof window !== 'undefined') {
-    if (window.crypto) {
-      return window.crypto.subtle || window.crypto.webkitSubtle
-    }
-
-    if (window.msCrypto) {
-      return window.msCrypto.subtle
-    }
-  }
-}
-
-function webCryptoHash (type) {
-  if (!webCrypto) {
-    throw new Error('Please use a browser with webcrypto support')
-  }
-
-  return (data, callback) => {
-    const res = webCrypto.digest({ name: type }, data)
-
-    if (typeof res.then !== 'function') { // IE11
-      res.onerror = () => {
-        callback(`Error hashing data using ${type}`)
-      }
-      res.oncomplete = (e) => {
-        callback(null, e.target.result)
-      }
-      return
-    }
-
-    nodeify(
-      res.then((raw) => new Buffer(new Uint8Array(raw))),
-      callback
-    )
-  }
-}
-
-function sha1 (buf, callback) {
-  webCryptoHash('SHA-1')(buf, callback)
-}
-
-function sha2256 (buf, callback) {
-  webCryptoHash('SHA-256')(buf, callback)
-}
-
-function sha2512 (buf, callback) {
-  webCryptoHash('SHA-512')(buf, callback)
-}
-
-function sha3 (buf, callback) {
-  const d = new SHA3.SHA3Hash()
-  const digest = new Buffer(d.update(buf).digest('hex'), 'hex')
-  callback(null, digest)
-}
-
-module.exports = {
-  sha1: sha1,
-  sha2256: sha2256,
-  sha2512: sha2512,
-  sha3: sha3
-}
diff --git a/src/crypto-sha1-2-browser.js b/src/crypto-sha1-2-browser.js
index 652cca93..fc846b15 100644
--- a/src/crypto-sha1-2-browser.js
+++ b/src/crypto-sha1-2-browser.js
@@ -1,3 +1,5 @@
+/* global self */
+
 'use strict'
 
 const nodeify = require('nodeify')
@@ -5,14 +7,13 @@ const nodeify = require('nodeify')
 const webCrypto = getWebCrypto()
 
 function getWebCrypto () {
-  if (typeof window !== 'undefined') {
-    if (window.crypto) {
-      return window.crypto.subtle || window.crypto.webkitSubtle
-    }
+  const globalCtx = typeof window !== 'undefined' ? window : self
+  if (globalCtx.crypto) {
+    return globalCtx.crypto.subtle || globalCtx.crypto.webkitSubtle
+  }
 
-    if (window.msCrypto) {
-      return window.msCrypto.subtle
-    }
+  if (globalCtx.msCrypto) {
+    return globalCtx.msCrypto.subtle
   }
 }