diff --git a/lib/crypto/sha256.js b/lib/crypto/sha256.js
index 91e85c3d..f931e661 100644
--- a/lib/crypto/sha256.js
+++ b/lib/crypto/sha256.js
@@ -251,23 +251,22 @@ SHA256Hmac.prototype.init = function init(data) {
     this.inner.init();
     this.inner.update(data);
     this.inner._finish(key);
-    key.fill(0, 32);
+    key.fill(0, 32, 64);
   } else {
     data.copy(key, 0);
     key.fill(0, data.length, 64);
   }
 
-  this.inner.init();
-  this.outer.init();
-
   for (i = 0; i < key.length; i++)
     key[i] ^= 0x36;
 
+  this.inner.init();
   this.inner.update(key);
 
   for (i = 0; i < key.length; i++)
     key[i] ^= 0x6a;
 
+  this.outer.init();
   this.outer.update(key);
 };