<?php
session_start();
/** PBKDF2 Implementation (as described in RFC 2898);
*
* @param string p password
* @param string s salt
* @param int c iteration count (use 1000 or higher)
* @param int kl derived key length
* @param string a hash algorithm
*
* @return string derived key
*/
function pbkdf2_helper_for_javascript( $p, $s, $c, $kl, $a = 'sha256' ) {
$hl = strlen( hash( $a, null, true ) );
$kb = ceil( $kl / $hl );
$dk = '';
for ( $block = 1; $block <= $kb; $block++ ) {
$ib = $b = hash_hmac( $a, $s . pack( 'N', $block ), $p, true );
for ( $i = 1; $i < $c; $i++ ) {
$ib ^= ( $b = hash_hmac( $a, $b, $p, true ) );
}
$dk .= $ib;
}
return substr( $dk, 0, $kl );
}
function dectypt_from_javascript_encrypt($dectypted_str, $callback = null) {
$salt = $_SESSION['password_salt'];
$secret_key = $_SESSION['password_secret'];
//get the cipher key
$key = pbkdf2_helper_for_javascript( $secret_key, $salt, 1000, 32 );
//get the IV
$iv64 = $_REQUEST['iv'];
$iv = base64_decode($iv64);
//get the HMAC
$hmac = $_REQUEST['hmac'];
# initialise mcrypt. NB Rijndael-128 covers all variants of AES
$td = mcrypt_module_open( MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_NOFB, '' );
# do encryption
$input = base64_decode($dectypted_str);
mcrypt_generic_init($td, $key, $iv);
$plain = mdecrypt_generic($td, $input);
mcrypt_generic_deinit($td);
# shutdown mcrypt
mcrypt_module_close($td);
# create HMAC for message
$hmacActual = hash_hmac('sha256', $plain, $iv);
if($hmac == $hmacActual) {
if ($callback && is_callable($callback)) {
$callback('success', $plain);
}
} else {
//解密失败，提示提醒用户
$callback('error', null);
}
//session 用完后清除
$_SESSION['password_secret'] = null;
}
if ($user = @$_POST['user'] && $password = @$_POST['password']) {
dectypt_from_javascript_encrypt($_POST['password'], function ($status, $password) {
print $password;
});
}
// 每次发生请求，生成一次key用来解密.
$key = uniqid();
//发送到客户端cookie
setcookie("password_secret", $key, 0);
setcookie("password_salt", "tuding_salt");
//并且保存到session用来后续的解密
$_SESSION['password_secret'] = $key;
$_SESSION['password_salt'] = 'tuding_salt';
?>
<!DOCTYPE HTML>
<html lang="en">
<head>
<meta charset="utf-8"/>
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js"></script>
<script type='text/javascript' src="http://crypto-js.googlecode.com/files/2.5.3-crypto.js"></script>
<script type='text/javascript' src="http://crypto-js.googlecode.com/files/2.5.3-sha256.js"></script>
<script type='text/javascript' src="http://crypto-js.googlecode.com/files/2.3.0-hmac.js"></script>
<script type='text/javascript' src="http://crypto-js.googlecode.com/files/2.3.0-pbkdf2.js"></script>
<script type='text/javascript' src="http://crypto-js.googlecode.com/files/2.3.0-aes.js"></script>
<script type='text/javascript' src="http://crypto-js.googlecode.com/files/2.5.3-blockmodes.js"></script>
<script type="text/javascript">
function doEncrypt(message) {
var secret = $.cookie('password_secret');
var salt = $.cookie('password_salt');
var bytes_iv = Crypto.util.randomBytes(16);
var base64_iv = Crypto.util.bytesToBase64(bytes_iv);
var hmac = Crypto.HMAC(Crypto.SHA256, message, bytes_iv);
var key = Crypto.PBKDF2(secret, salt, 32, {hasher:Crypto.SHA256, iterations:1000, asBytes:true});
var cipher =Crypto.AES.encrypt(message, key, {iv:bytes_iv, mode:new Crypto.mode.OFB, asBytes:false});
return {iv: base64_iv, hmac: hmac, cipher: cipher};
}
$(document).ready(function () {
$('#submit').click(function () {
var user = $('input[name="user"]').val();
var pwd = $('input[name="password"]').val();
try {
var encrypt_pwd = doEncrypt(pwd);
$('input[name="hmac"]').val(encrypt_pwd['hmac']);
$('input[name="password"]').val(encrypt_pwd['cipher']);
$('input[name="iv"]').val(encrypt_pwd['iv']);
}
catch (exception) {
//TODO:
}
});
});
</script>
</head>
<body>
<form action="/index_bk.php" name="login" method="post">
<div>
<label for="user">User</label>
<input type="text" value="" placeholder="Your login name" name="user"/>
</div>
<div>
<label for="password">Password</label>
<input type="password" placeholder="your password" name="password" />
<input type="hidden" name="hmac" value=""/>
<input type="hidden" name="iv" value=""/>
</div>
<input type="submit" value="Login" id="submit"/>
</form>
</body>
</html>
