Merge #1650 다양하게 활용 가능한 암호화 클래스 추가 by kijin

* pr/1650:
  Simplify IV creation routine by reusing Password class
  Add currentSessionOnly option to Crypto class
  Add Crypto class compatible with defuse/php-encryption
This commit is contained in:
Kijin Sung 2015-10-08 15:03:28 +09:00
commit 9dbe64e0da
2 changed files with 358 additions and 0 deletions

View file

@ -0,0 +1,357 @@
<?php
/* Copyright (C) NAVER <http://www.navercorp.com> */
/**
* This class makes encryption and digital signing easy to use in XE.
*
* The encryption methods use AES-128, and is fully compatible with
* https://github.com/defuse/php-encryption
* except that it uses base64-encoded keys and ciphertexts.
*
* The digital signature methods is based on the same SHA-256 based
* key derivation function used by the encryption methods.
*
* A key is automatically generated and saved to the files/config directory
* when first invoked. The same key will be used for all subsequent
* method calls that do not specify a different key.
* The key must be a binary string exactly 16 bytes long.
*
* @file Crypto.class.php
* @author Kijin Sung (kijin@kijinsung.com)
* @package /classes/security
* @version 1.0
*/
class Crypto
{
/**
* @brief Default configuration
*/
const ENCRYPTION_ALGO = 'aes-128';
const ENCRYPTION_MODE = 'cbc';
const ENCRYPTION_BLOCK_SIZE = 16;
const ENCRYPTION_KEY_SIZE = 16;
const ENCRYPTION_KEY_INFO = 'DefusePHP|KeyForEncryption';
const ENCRYPTION_MAC_ALGO = 'sha256';
const ENCRYPTION_MAC_SIZE = 32;
const ENCRYPTION_MAC_INFO = 'DefusePHP|KeyForAuthentication';
const SIGNATURE_ALGO = 'sha256';
const SIGNATURE_SIZE = '32';
/**
* @brief The default key
*/
protected static $_default_key = null;
/**
* @brief The currently selected extension
*/
protected static $_extension = null;
/**
* @brief If this is true, encryption and signature are only valid in current session
*/
protected $_current_session_only = false;
/**
* @brief Constructor
*/
public function __construct()
{
if(function_exists('openssl_encrypt'))
{
self::$_extension = 'openssl';
}
elseif(function_exists('mcrypt_encrypt'))
{
self::$_extension = 'mcrypt';
}
else
{
throw new Exception('Crypto class requires openssl or mcrypt extension.');
}
}
/**
* @brief Check if cryptography is supported on this server
* @return bool
*/
public static function isSupported()
{
return (function_exists('openssl_encrypt') || function_exists('mcrypt_encrypt'));
}
/**
* @brief Make encryption and signature only valid in current session
* @return void
*/
public function currentSessionOnly()
{
$this->_current_session_only = true;
}
/**
* @brief Encrypt a string
* @param string $plaintext The string to encrypt
* @param string $key Optional key. If empty, default key will be used.
* @return string
*/
public function encrypt($plaintext, $key = null)
{
if($key === null || $key === '')
{
$key = $this->_getSessionKey();
}
// Generate subkey for encryption
$enc_key = self::_defuseCompatibleHKDF($key, self::ENCRYPTION_KEY_INFO);
// Generate IV
$iv = self::_createIV();
// Encrypt the plaintext
if(self::$_extension === 'openssl')
{
$openssl_method = self::ENCRYPTION_ALGO . '-' . self::ENCRYPTION_MODE;
$ciphertext = openssl_encrypt($plaintext, $openssl_method, $enc_key, OPENSSL_RAW_DATA, $iv);
}
else
{
$mcrypt_method = str_replace('aes', 'rijndael', self::ENCRYPTION_ALGO);
$plaintext = self::_applyPKCS7Padding($plaintext, self::ENCRYPTION_BLOCK_SIZE);
$ciphertext = mcrypt_encrypt($mcrypt_method, $enc_key, $plaintext, self::ENCRYPTION_MODE, $iv);
}
// Generate MAC
$mac_key = self::_defuseCompatibleHKDF($key, self::ENCRYPTION_MAC_INFO);
$mac = hash_hmac(self::ENCRYPTION_MAC_ALGO, ($iv . $ciphertext), $mac_key, true);
// Return the MAC, IV, and ciphertext as a base64 encoded string
return base64_encode($mac . $iv . $ciphertext);
}
/**
* @brief Decrypt a string
* @param string $ciphertext The string to decrypt
* @param string $key Optional key. If empty, default key will be used.
* @return string
*/
public function decrypt($ciphertext, $key = null)
{
if($key === null || $key === '')
{
$key = $this->_getSessionKey();
}
// Base64 decode the ciphertext and check the length
$ciphertext = @base64_decode($ciphertext);
if(strlen($ciphertext) < (self::ENCRYPTION_MAC_SIZE + (self::ENCRYPTION_BLOCK_SIZE * 2)))
{
return false;
}
// Extract MAC and IV from the remainder of the ciphertext
$mac = substr($ciphertext, 0, self::ENCRYPTION_MAC_SIZE);
$iv = substr($ciphertext, self::ENCRYPTION_MAC_SIZE, self::ENCRYPTION_BLOCK_SIZE);
$ciphertext = substr($ciphertext, self::ENCRYPTION_MAC_SIZE + self::ENCRYPTION_BLOCK_SIZE);
// Validate MAC
$mac_key = self::_defuseCompatibleHKDF($key, self::ENCRYPTION_MAC_INFO);
$mac_compare = hash_hmac(self::ENCRYPTION_MAC_ALGO, ($iv . $ciphertext), $mac_key, true);
$oPassword = new Password();
if(!$oPassword->strcmpConstantTime($mac, $mac_compare))
{
return false;
}
// Generate subkey for encryption
$enc_key = self::_defuseCompatibleHKDF($key, self::ENCRYPTION_KEY_INFO);
// Decrypt the ciphertext
if (self::$_extension === 'openssl')
{
$openssl_method = self::ENCRYPTION_ALGO . '-' . self::ENCRYPTION_MODE;
$plaintext = openssl_decrypt($ciphertext, $openssl_method, $enc_key, OPENSSL_RAW_DATA, $iv);
}
else
{
$mcrypt_method = str_replace('aes', 'rijndael', self::ENCRYPTION_ALGO);
$plaintext = @mcrypt_decrypt($mcrypt_method, $enc_key, $ciphertext, self::ENCRYPTION_MODE, $iv);
if($plaintext === false)
{
return false;
}
$plaintext = self::_stripPKCS7Padding($plaintext, self::ENCRYPTION_BLOCK_SIZE);
if($plaintext === false)
{
return false;
}
}
// Return the plaintext
return $plaintext;
}
/**
* @brief Create a digital signature of a string
* @param string $plaintext The string to sign
* @param string $key Optional key. If empty, default key will be used.
* @return string
*/
public function createSignature($plaintext, $key = null)
{
if($key === null || $key === '')
{
$key = $this->_getSessionKey();
}
// Generate a signature using HMAC
return bin2hex(self::_defuseCompatibleHKDF($plaintext, $key));
}
/**
* @brief Verify a digital signature
* @param string $signature The signature to verify
* @param string $plaintext The string to verify
* @param string $key Optional key. If empty, default key will be used.
* @return bool
*/
public function verifySignature($signature, $plaintext, $key = null)
{
if($key === null || $key === '')
{
$key = $this->_getSessionKey();
}
// Verify the signature using HMAC
$oPassword = new Password();
$compare = bin2hex(self::_defuseCompatibleHKDF($plaintext, $key));
return $oPassword->strcmpConstantTime($signature, $compare);
}
/**
* @brief Get the default key applicable to this instance
* @return string
*/
protected function _getSessionKey()
{
if($this->_current_session_only)
{
if(!isset($_SESSION['XE_CRYPTO_SESSKEY']))
{
$_SESSION['XE_CRYPTO_SESSKEY'] = self::_createSecureKey();
}
$session_key = base64_decode($_SESSION['XE_CRYPTO_SESSKEY']);
return strval(self::_getDefaultKey()) ^ strval($session_key);
}
else
{
return strval(self::_getDefaultKey());
}
}
/**
* @brief Get the default key
* @return string
*/
protected static function _getDefaultKey()
{
if(self::$_default_key !== null)
{
return base64_decode(self::$_default_key);
}
else
{
$file_name = _XE_PATH_ . 'files/config/crypto.config.php';
if(file_exists($file_name) && is_readable($file_name))
{
$key = (include $file_name);
}
if(!isset($key) || !is_string($key))
{
$key = self::_createSecureKey();
self::_setDefaultKey($key);
}
return base64_decode(self::$_default_key = $key);
}
}
/**
* @brief Set the default key
* @param string $key The default key
* @return void
*/
protected static function _setDefaultKey($key)
{
self::$_default_key = $key = trim($key);
$file_name = _XE_PATH_ . 'files/config/crypto.config.php';
$file_content = '<?php return ' . var_export($key, true) . ';' . PHP_EOL;
FileHandler::writeFile($file_name, $file_content);
}
/**
* @brief Create a secure key
* @return string
*/
protected static function _createSecureKey()
{
$oPassword = new Password();
return base64_encode($oPassword->createSecureSalt(ENCRYPTION_KEY_SIZE, 'binary'));
}
/**
* @brief Create an IV
* @return string
*/
protected static function _createIV()
{
$oPassword = new Password();
return $oPassword->createSecureSalt(self::ENCRYPTION_BLOCK_SIZE, 'binary');
}
/**
* @brief Apply PKCS#7 padding to a string
* @param string $str The string
* @param int $block_size The block size
* @return string
*/
protected static function _applyPKCS7Padding($str, $block_size)
{
$padding_size = $block_size - (strlen($str) % $block_size);
if ($padding_size === 0) $padding_size = $block_size;
return $str . str_repeat(chr($padding_size), $padding_size);
}
/**
* @brief Remove PKCS#7 padding from a string
* @param string $str The string
* @param int $block_size The block size
* @return string
*/
protected static function _stripPKCS7Padding($str, $block_size)
{
if (strlen($str) % $block_size !== 0) return false;
$padding_size = ord(substr($str, -1));
if ($padding_size < 1 || $padding_size > $block_size) return false;
if (substr($str, (-1 * $padding_size)) !== str_repeat(chr($padding_size), $padding_size)) return false;
return substr($str, 0, strlen($str) - $padding_size);
}
/**
* @brief HKDF function compatible with defuse/php-encryption
* @return string
*/
protected static function _defuseCompatibleHKDF($key, $info)
{
$salt = str_repeat("\x00", self::ENCRYPTION_MAC_SIZE);
$prk = hash_hmac(self::ENCRYPTION_MAC_ALGO, $key, $salt, true);
$t = $last_block = '';
for ($block_index = 1; strlen($t) < self::ENCRYPTION_KEY_SIZE; $block_index++)
{
$t .= $last_block = hash_hmac(self::ENCRYPTION_MAC_ALGO, ($last_block . $info . chr($block_index)), $prk, true);
}
return substr($t, 0, self::ENCRYPTION_KEY_SIZE);
}
}
/* End of file : Crypto.class.php */
/* Location: ./classes/security/Crypto.class.php */

View file

@ -342,6 +342,7 @@ $GLOBALS['__xe_autoload_file_map'] = array_change_key_case(array(
'ModuleObject' => 'classes/module/ModuleObject.class.php', 'ModuleObject' => 'classes/module/ModuleObject.class.php',
'Object' => 'classes/object/Object.class.php', 'Object' => 'classes/object/Object.class.php',
'PageHandler' => 'classes/page/PageHandler.class.php', 'PageHandler' => 'classes/page/PageHandler.class.php',
'Crypto' => 'classes/security/Crypto.class.php',
'EmbedFilter' => 'classes/security/EmbedFilter.class.php', 'EmbedFilter' => 'classes/security/EmbedFilter.class.php',
'IpFilter' => 'classes/security/IpFilter.class.php', 'IpFilter' => 'classes/security/IpFilter.class.php',
'Password' => 'classes/security/Password.class.php', 'Password' => 'classes/security/Password.class.php',