diff --git a/index.js b/index.js
index c9189fe..9e7624c 100644
--- a/index.js
+++ b/index.js
@@ -2180,6 +2180,10 @@ var crypto_secretbox_KEYBYTES = 32,
     crypto_sign_SEEDBYTES = 32,
     crypto_hash_BYTES = 64;
 
+sodium.memzero = function (len, offset) {
+  for (var i = offset; i < len; i++) arr[i] = 0;
+}
+
 sodium.randombytes_buf = randombytes_buf
 
 sodium.crypto_sign_BYTES = crypto_sign_BYTES