1 files changed, 4 insertions, 2 deletions
diff --git a/lib/crypto.js b/lib/crypto.js
index 2f0a00b152..91106b35f6 100644
--- a/lib/crypto.js
+++ b/lib/crypto.js
@@ -22,6 +22,8 @@
 // Note: In 0.8 and before, crypto functions all defaulted to using
 // binary-encoded strings rather than buffers.
 
+'use strict';
+
 exports.DEFAULT_ENCODING = 'buffer';
 
 try {
@@ -600,11 +602,11 @@ function pbkdf2(password, salt, iterations, keylen, digest, callback) {
   // at this point, we need to handle encodings.
   var encoding = exports.DEFAULT_ENCODING;
   if (callback) {
-    function next(er, ret) {
+    var next = function(er, ret) {
       if (ret)
         ret = ret.toString(encoding);
       callback(er, ret);
-    }
+    };
     binding.PBKDF2(password, salt, iterations, keylen, digest, next);
   } else {
     var ret = binding.PBKDF2(password, salt, iterations, keylen, digest);