diff --git a/README.md b/README.md
index d52eb9a..014f608 100644
--- a/README.md
+++ b/README.md
@@ -40,7 +40,7 @@ line = readlineSync.prompt([options])
 ```
 
 Readies readline for input from the user, putting the current `setPrompt` options on a new line, giving the user a new spot to write.  
-If `{noEchoBack: true}` is specified to `options`, echo back is avoided. It is used to hide the password which is typed by user on screen. *See [Note](#note) for security.*
+If `{noEchoBack: true}` is specified to `options`, echo back is avoided. It is used to hide the password which is typed by user on screen.
 
 ### question
 
@@ -50,7 +50,7 @@ line = readlineSync.question([query[, options]])
 
 Displays the `query` to the user, and then returns the user's response after it has been typed.  
 `query` is converted to string (i.e. `toString` method is called) before it is displayed every time.  
-If `{noEchoBack: true}` is specified to `options`, echo back is avoided. It is used to hide the password which is typed by user on screen. *See [Note](#note) for security.*
+If `{noEchoBack: true}` is specified to `options`, echo back is avoided. It is used to hide the password which is typed by user on screen.
 
 ### setEncoding
 
@@ -104,9 +104,8 @@ try {
 }
 ```
 
-+ If `options.noEchoBack` is used, the text that input by user is saved to temporary file (e.g. `/tmp/readline-sync.stdout`). This file is removed immediately after reading is done, but you have to be careful about it because this text is *plain*. Removing the file might fail, or the file might be peeped before it is removed.
-
 ## Release History
+ * 2014-07-13			v0.4.3			fixed #6: Crypto input data.
  * 2014-07-12			v0.4.2			`setPrompt()` and `setEncoding()` return current value.
  * 2014-07-12			v0.4.1			`setPrompt()` and `question()` accept the value which is not string too (e.g. number, Date, Object, etc.).
  * 2014-07-12			v0.4.0			Add `options.noEchoBack`.
diff --git a/lib/encrypt.js b/lib/encrypt.js
new file mode 100644
index 0000000..b1e475b
--- /dev/null
+++ b/lib/encrypt.js
@@ -0,0 +1,16 @@
+var algorithmCipher = 'aes-256-cbc',
+  cipher = require('crypto').createCipher(algorithmCipher, process.argv[2]),
+  stdin = process.stdin,
+  stdout = process.stdout,
+  crypted = '';
+
+stdin.resume();
+stdin.setEncoding('utf8');
+stdin.on('data', function(d) {
+  crypted += cipher.update(d, 'utf8', 'hex');
+});
+stdin.on('end', function() {
+  stdout.write(crypted + cipher.final('hex'), 'binary', function() {
+    process.exit(0);
+  });
+});
diff --git a/lib/readline-sync.js b/lib/readline-sync.js
index 6a41353..536c0f0 100644
--- a/lib/readline-sync.js
+++ b/lib/readline-sync.js
@@ -8,14 +8,18 @@
 
 'use strict';
 
-var promptText = '> ',
-  encoding = 'utf8',
+var
   BUF_SIZE = 256,
+  ALGORITHM_CIPHER = 'aes-256-cbc',
+  ALGORITHM_HASH = 'sha256',
+
+  promptText = '> ',
+  encoding = 'utf8',
   fs = require('fs'),
   stdin = process.stdin,
   stdout = process.stdout,
   buffer = new Buffer(BUF_SIZE),
-  useShell = true, print, tempdir;
+  useShell = true, print, tempdir, salt = 0;
 
 function _readlineSync(display, options) {
   var input = '', rsize, err;
@@ -78,18 +82,29 @@ function _readlineShell(noEchoBack) {
     pathStdout = getTempfile('readline-sync.stdout'),
     pathStatus = getTempfile('readline-sync.status'),
     pathDone   = getTempfile('readline-sync.done'),
-    optEchoBack = noEchoBack ? ' noechoback' : '';
+    optEchoBack = noEchoBack ? ' noechoback' : '',
+    crypto = require('crypto'), shasum, decipher, password;
+
+  shasum = crypto.createHash(ALGORITHM_HASH);
+  shasum.update('' + process.pid + (salt++) + Math.random());
+  password = shasum.digest('hex');
+  decipher = crypto.createDecipher(ALGORITHM_CIPHER, password);
 
   if (process.platform === 'win32') {
     // The quote (") is escaped by node before parsed by shell. Then use ENV{Q}.
     shellPath = 'cmd.exe';
     args = ['/V:ON', '/S', '/C',
-      '%Q%' + __dirname + '\\read.bat%Q%' + optEchoBack + ' >%Q%' + pathStdout +
-      '%Q% & (echo !ERRORLEVEL!)>%Q%' + pathStatus + '%Q% & (echo 1)>%Q%' + pathDone + '%Q%'];
+      '%Q%' + __dirname + '\\read.bat%Q%' + optEchoBack +
+      ' |%Q%' + process.execPath + '%Q% %Q%' + __dirname + '\\encrypt.js%Q% %Q%' + password + '%Q%' +
+      ' >%Q%' + pathStdout + '%Q%' +
+      ' & (echo !ERRORLEVEL!)>%Q%' + pathStatus + '%Q% & (echo 1)>%Q%' + pathDone + '%Q%'];
   } else {
     shellPath = '/bin/sh';
-    args = ['-c', '(' + shellPath + ' "' + __dirname + '/read.sh"' + optEchoBack + ') >"' + pathStdout +
-      '"; echo $? >"' + pathStatus + '"; echo 1 >"' + pathDone + '"'];
+    args = ['-c',
+      '(' + shellPath + ' "' + __dirname + '/read.sh"' + optEchoBack + ')' +
+      ' |"' + process.execPath + '" "' + __dirname + '/encrypt.js" "' + password + '"' +
+      ' >"' + pathStdout + '";' +
+      ' echo $? >"' + pathStatus + '"; echo 1 >"' + pathDone + '"'];
   }
 
   stdin.pause(); // re-start in child process
@@ -99,7 +114,9 @@ function _readlineShell(noEchoBack) {
     if (fs.readFileSync(pathDone, {encoding: encoding}).trim() === '1') { break; }
   }
   if (fs.readFileSync(pathStatus, {encoding: encoding}).trim() === '0') {
-    shellStdout = fs.readFileSync(pathStdout, {encoding: encoding});
+    shellStdout =
+      decipher.update(fs.readFileSync(pathStdout, {encoding: 'binary'}), 'hex', encoding) +
+      decipher.final(encoding);
   }
 
   fs.unlinkSync(pathStdout);
diff --git a/package.json b/package.json
index 4aa15a6..32d08fe 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "readline-sync",
   "description": "Synchronous Readline",
-  "version": "0.4.2",
+  "version": "0.4.3",
   "homepage": "https://github.com/anseki/readline-sync",
   "author": {
     "name": "anseki"