diff --git a/sea.js b/sea.js
index c496e2df..92a0a0c6 100644
--- a/sea.js
+++ b/sea.js
@@ -3,9 +3,7 @@
   /* UNBUILD */
   var root;
   if(typeof window !== "undefined"){ root = window }
-  if(typeof Buffer === "undefined") {
-    global.Buffer = require("buffer").Buffer
-  }
+  
   if(typeof global !== "undefined"){ root = global }
   root = root || {};
   var console = root.console || {log: function(){}};
@@ -50,10 +48,12 @@
   })(USE, './https');
 
   ;USE(function(module){
-    if(typeof global !== "undefined"){
-      var g = global;
-      g.btoa = function (data) { return Buffer.from(data, "binary").toString("base64"); };
-      g.atob = function (data) { return Buffer.from(data, "base64").toString("binary"); };
+    if(typeof Buffer === "undefined") {
+      root.Buffer = require("buffer").Buffer
+    }
+    if(typeof btoa !== "undefined"){
+      root.btoa = function (data) { return Buffer.from(data, "binary").toString("base64"); };
+      root.atob = function (data) { return Buffer.from(data, "base64").toString("binary"); };
     }
   })(USE, './base64');
 
diff --git a/sea/base64.js b/sea/base64.js
index 5a87f29e..48b78725 100644
--- a/sea/base64.js
+++ b/sea/base64.js
@@ -1,7 +1,9 @@
 
-    if(typeof global !== "undefined"){
-      var g = global;
-      g.btoa = function (data) { return Buffer.from(data, "binary").toString("base64"); };
-      g.atob = function (data) { return Buffer.from(data, "base64").toString("binary"); };
+    if(typeof Buffer === "undefined") {
+      root.Buffer = require("buffer").Buffer
+    }
+    if(typeof btoa !== "undefined"){
+      root.btoa = function (data) { return Buffer.from(data, "binary").toString("base64"); };
+      root.atob = function (data) { return Buffer.from(data, "base64").toString("binary"); };
     }
   
\ No newline at end of file
diff --git a/sea/shim.js b/sea/shim.js
index 6f73e259..42716477 100644
--- a/sea/shim.js
+++ b/sea/shim.js
@@ -6,9 +6,6 @@
 
     if(SEA.window){
       api.crypto = window.crypto || window.msCrypto || require('isomorphic-webcrypto');
-      if(!api.crypto) {
-        api.crypto = require('isomorphic-webcrypto');
-      }
       api.subtle = (api.crypto||o).subtle || (api.crypto||o).webkitSubtle;
       api.TextEncoder = window.TextEncoder;
       api.TextDecoder = window.TextDecoder;