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630 lines
26 KiB
630 lines
26 KiB
<?php |
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/** |
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* @link http://www.yiiframework.com/ |
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* @copyright Copyright (c) 2008 Yii Software LLC |
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* @license http://www.yiiframework.com/license/ |
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*/ |
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namespace yii\base; |
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use yii\helpers\StringHelper; |
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use Yii; |
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/** |
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* Security provides a set of methods to handle common security-related tasks. |
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* |
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* In particular, Security supports the following features: |
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* |
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* - Encryption/decryption: [[encryptByKey()]], [[decryptByKey()]], [[encryptByPassword()]] and [[decryptByPassword()]] |
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* - Key derivation using standard algorithms: [[pbkdf2()]] and [[hkdf()]] |
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* - Data tampering prevention: [[hashData()]] and [[validateData()]] |
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* - Password validation: [[generatePasswordHash()]] and [[validatePassword()]] |
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* |
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* > Note: this class requires 'mcrypt' PHP extension. For the highest security level PHP version >= 5.5.0 is recommended. |
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* |
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* @author Qiang Xue <qiang.xue@gmail.com> |
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* @author Tom Worster <fsb@thefsb.org> |
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* @author Klimov Paul <klimov.paul@gmail.com> |
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* @since 2.0 |
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*/ |
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class Security extends Component |
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{ |
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/** |
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* Cipher algorithm for mcrypt module. |
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* AES has 128-bit block size and three key sizes: 128, 192 and 256 bits. |
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* mcrypt offers the Rijndael cipher with block sizes of 128, 192 and 256 |
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* bits but only the 128-bit Rijndael is standardized in AES. |
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* So to use AES in mycrypt, specify `'rijndael-128'` cipher and mcrypt |
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* chooses the appropriate AES based on the length of the supplied key. |
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*/ |
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const MCRYPT_CIPHER = 'rijndael-128'; |
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/** |
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* Block cipher operation mode for mcrypt module. |
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*/ |
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const MCRYPT_MODE = 'cbc'; |
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/** |
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* Size in bytes of encryption key, message authentication key and KDF salt. |
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*/ |
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const KEY_SIZE = 16; |
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/** |
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* Hash algorithm for key derivation. |
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*/ |
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const KDF_HASH = 'sha256'; |
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/** |
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* Hash algorithm for message authentication. |
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*/ |
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const MAC_HASH = 'sha256'; |
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/** |
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* HKDF info value for derivation of message authentication key. |
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*/ |
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const AUTH_KEY_INFO = 'AuthorizationKey'; |
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/** |
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* @var integer derivation iterations count. |
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* Set as high as possible to hinder dictionary password attacks. |
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*/ |
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public $derivationIterations = 100000; |
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/** |
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* @var string strategy, which should be used to generate password hash. |
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* Available strategies: |
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* - 'password_hash' - use of PHP `password_hash()` function with PASSWORD_DEFAULT algorithm. |
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* This option is recommended, but it requires PHP version >= 5.5.0 |
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* - 'crypt' - use PHP `crypt()` function. |
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*/ |
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public $passwordHashStrategy = 'crypt'; |
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private $_cryptModule; |
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/** |
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* Encrypts data using a password. |
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* Derives keys for encryption and authentication from the password using PBKDF2 and a random salt, |
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* which is deliberately slow to protect against dictionary attacks. Use [[encryptByKey()]] to |
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* encrypt fast using a cryptographic key rather than a password. Key derivation time is |
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* determined by [[$derivationIterations]], which should be set as high as possible. |
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* The encrypted data includes a keyed message authentication code (MAC) so there is no need |
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* to hash input or output data. |
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* > Note: Avoid encrypting with passwords wherever possible. Nothing can protect against |
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* poor-quality or compromosed passwords. |
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* @param string $data the data to encrypt |
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* @param string $password the password to use for encryption |
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* @return string the encrypted data |
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* @see decryptByPassword() |
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* @see encryptByKey() |
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*/ |
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public function encryptByPassword($data, $password) |
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{ |
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return $this->encrypt($data, true, $password, null); |
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} |
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/** |
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* Encrypts data using a cryptograhic key. |
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* Derives keys for encryption and authentication from the input key using HKDF and a random salt, |
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* which is very fast relative to [[encryptByPassword()]]. The input key must be properly |
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* random -- use [[generateRandomKey()]] to generate keys. |
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* The encrypted data includes a keyed message authentication code (MAC) so there is no need |
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* to hash input or output data. |
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* @param string $data the data to encrypt |
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* @param string $inputKey the input to use for encryption and authentication |
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* @param string $info optional context and application specific information, see [[hkdf()]] |
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* @return string the encrypted data |
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* @see decryptByPassword() |
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* @see encryptByKey() |
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*/ |
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public function encryptByKey($data, $inputKey, $info = null) |
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{ |
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return $this->encrypt($data, false, $inputKey, $info); |
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} |
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/** |
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* Verifies and decrypts data encrypted with [[encryptByPassword()]]. |
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* @param string $data the encrypted data to decrypt |
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* @param string $password the password to use for decryption |
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* @return bool|string the decrypted data or false on authentication failure |
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* @see encryptByPassword() |
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*/ |
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public function decryptByPassword($data, $password) |
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{ |
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return $this->decrypt($data, true, $password, null); |
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} |
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/** |
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* Verifies and decrypts data encrypted with [[encryptByPassword()]]. |
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* @param string $data the encrypted data to decrypt |
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* @param string $inputKey the input to use for encryption and authentication |
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* @param string $info optional context and application specific information, see [[hkdf()]] |
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* @return bool|string the decrypted data or false on authentication failure |
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* @see encryptByKey() |
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*/ |
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public function decryptByKey($data, $inputKey, $info = null) |
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{ |
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return $this->decrypt($data, false, $inputKey, $info); |
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} |
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/** |
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* Initializes the mcrypt module. |
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* @return resource the mcrypt module handle. |
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* @throws InvalidConfigException if mcrypt extension is not installed |
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* @throws Exception if mcrypt initialization fails |
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*/ |
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protected function getCryptModule() |
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{ |
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if ($this->_cryptModule === null) { |
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if (!extension_loaded('mcrypt')) { |
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throw new InvalidConfigException('The mcrypt PHP extension is not installed.'); |
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} |
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$this->_cryptModule = @mcrypt_module_open(self::MCRYPT_CIPHER, '', self::MCRYPT_MODE, ''); |
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if ($this->_cryptModule === false) { |
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$this->_cryptModule = null; |
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throw new Exception('Failed to initialize the mcrypt module.'); |
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} |
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} |
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return $this->_cryptModule; |
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} |
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public function __destruct() |
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{ |
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if ($this->_cryptModule !== null) { |
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mcrypt_module_close($this->_cryptModule); |
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$this->_cryptModule = null; |
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} |
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} |
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/** |
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* Encrypts data. |
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* @param string $data data to be encrypted |
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* @param bool $passwordBased set true to use password-based key derivation |
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* @param string $secret the encryption password or key |
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* @param string $info context/application specific information, e.g. a user ID |
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* See [RFC 5869 Section 3.2](https://tools.ietf.org/html/rfc5869#section-3.2) for more details. |
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* @return string the encrypted data |
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* @throws Exception if PHP Mcrypt extension is not loaded or failed to be initialized |
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* @see decrypt() |
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*/ |
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protected function encrypt($data, $passwordBased, $secret, $info) |
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{ |
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$module = $this->getCryptModule(); |
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$keySalt = $this->generateRandomKey(self::KEY_SIZE); |
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if ($passwordBased) { |
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$key = $this->pbkdf2(self::KDF_HASH, $secret, $keySalt, $this->derivationIterations, self::KEY_SIZE); |
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} else { |
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$key = $this->hkdf(self::KDF_HASH, $secret, $keySalt, $info, self::KEY_SIZE); |
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} |
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$data = $this->addPadding($data); |
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$ivSize = mcrypt_enc_get_iv_size($module); |
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$iv = mcrypt_create_iv($ivSize, MCRYPT_DEV_URANDOM); |
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mcrypt_generic_init($module, $key, $iv); |
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$encrypted = mcrypt_generic($module, $data); |
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mcrypt_generic_deinit($module); |
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$authKey = $this->hkdf(self::KDF_HASH, $key, null, self::AUTH_KEY_INFO, self::KEY_SIZE); |
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$hashed = $this->hashData($iv . $encrypted, $authKey); |
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/* |
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* Output: [keySalt][MAC][IV][ciphertext] |
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* - keySalt is KEY_SIZE bytes long |
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* - MAC: message authentication code, length same as the output of MAC_HASH |
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* - IV: initialization vector, length set by CRYPT_CIPHER and CRYPT_MODE, mcrypt_enc_get_iv_size() |
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*/ |
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return $keySalt . $hashed; |
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} |
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/** |
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* Decrypts data. |
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* @param string $data encrypted data to be decrypted. |
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* @param bool $passwordBased set true to use password-based key derivation |
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* @param string $secret the decryption password or key |
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* @param string $info context/application specific information, @see encrypt() |
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* @return bool|string the decrypted data or false on authentication failure |
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* @see encrypt() |
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*/ |
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protected function decrypt($data, $passwordBased, $secret, $info) |
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{ |
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$keySalt = StringHelper::byteSubstr($data, 0, self::KEY_SIZE); |
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if ($passwordBased) { |
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$key = $this->pbkdf2(self::KDF_HASH, $secret, $keySalt, $this->derivationIterations, self::KEY_SIZE); |
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} else { |
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$key = $this->hkdf(self::KDF_HASH, $secret, $keySalt, $info, self::KEY_SIZE); |
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} |
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$authKey = $this->hkdf(self::KDF_HASH, $key, null, self::AUTH_KEY_INFO, self::KEY_SIZE); |
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$data = $this->validateData(StringHelper::byteSubstr($data, self::KEY_SIZE, null), $authKey); |
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if ($data === false) { |
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return false; |
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} |
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$module = $this->getCryptModule(); |
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$ivSize = mcrypt_enc_get_iv_size($module); |
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$iv = StringHelper::byteSubstr($data, 0, $ivSize); |
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$encrypted = StringHelper::byteSubstr($data, $ivSize, null); |
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mcrypt_generic_init($module, $key, $iv); |
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$decrypted = mdecrypt_generic($module, $encrypted); |
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mcrypt_generic_deinit($module); |
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return $this->stripPadding($decrypted); |
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} |
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/** |
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* Adds a padding to the given data (PKCS #7). |
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* @param string $data the data to pad |
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* @return string the padded data |
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*/ |
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protected function addPadding($data) |
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{ |
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$module = $this->getCryptModule(); |
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$blockSize = mcrypt_enc_get_block_size($module); |
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$pad = $blockSize - (StringHelper::byteLength($data) % $blockSize); |
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return $data . str_repeat(chr($pad), $pad); |
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} |
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/** |
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* Strips the padding from the given data. |
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* @param string $data the data to trim |
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* @return string the trimmed data |
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*/ |
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protected function stripPadding($data) |
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{ |
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$end = StringHelper::byteSubstr($data, -1, null); |
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$last = ord($end); |
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$n = StringHelper::byteLength($data) - $last; |
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if (StringHelper::byteSubstr($data, $n, null) === str_repeat($end, $last)) { |
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return StringHelper::byteSubstr($data, 0, $n); |
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} |
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return false; |
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} |
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/** |
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* Derives a key from the given input key using the standard HKDF algorithm. |
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* Implements HKDF specified in [RFC 5869](https://tools.ietf.org/html/rfc5869). |
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* Recommend use one of the SHA-2 hash algorithms: sha224, sha256, sha384 or sha512. |
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* @param string $algo a hash algorithm supported by `hash_hmac()`, e.g. 'SHA-256' |
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* @param string $inputKey the source key |
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* @param string $salt the random salt |
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* @param string $info optional info to bind the derived key material to application- |
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* and context-specific information, e.g. a user ID or API version, see |
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* [RFC 5869](https://tools.ietf.org/html/rfc5869) |
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* @param int $length length of the output key in bytes. If 0, the output key is |
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* the length of the hash algorithm output. |
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* @throws InvalidParamException |
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* @return string the derived key |
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*/ |
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public function hkdf($algo, $inputKey, $salt = null, $info = null, $length = 0) |
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{ |
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$test = @hash_hmac($algo, '', '', true); |
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if (!$test) { |
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throw new InvalidParamException('Failed to generate HMAC with hash algorithm: ' . $algo); |
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} |
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$hashLength = StringHelper::byteLength($test); |
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if (is_string($length) && preg_match('{^\d{1,16}$}', $length)) { |
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$length = (int) $length; |
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} |
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if (!is_integer($length) || $length < 0 || $length > 255 * $hashLength) { |
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throw new InvalidParamException('Invalid length'); |
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} |
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$blocks = $length !== 0 ? ceil($length / $hashLength) : 1; |
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if ($salt === null) { |
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$salt = str_repeat("\0", $hashLength); |
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} |
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$prKey = hash_hmac($algo, $inputKey, $salt, true); |
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$hmac = ''; |
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$outputKey = ''; |
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for ($i = 1; $i <= $blocks; $i++) { |
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$hmac = hash_hmac($algo, $hmac . $info . chr($i), $prKey, true); |
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$outputKey .= $hmac; |
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} |
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if ($length !== 0) { |
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$outputKey = StringHelper::byteSubstr($outputKey, 0, $length); |
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} |
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return $outputKey; |
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} |
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/** |
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* Derives a key from the given password using the standard PBKDF2 algorithm. |
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* Implements HKDF2 specified in [RFC 2898](http://tools.ietf.org/html/rfc2898#section-5.2) |
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* Recommend use one of the SHA-2 hash algorithms: sha224, sha256, sha384 or sha512. |
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* @param string $algo a hash algorithm supported by `hash_hmac()`, e.g. 'SHA-256' |
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* @param string $password the source password |
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* @param string $salt the random salt |
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* @param int $iterations the number of iterations of the hash algorithm. Set as high as |
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* possible to hinder dictionary password attacks. |
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* @param int $length length of the output key in bytes. If 0, the output key is |
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* the length of the hash algorithm output. |
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* @throws InvalidParamException |
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* @return string the derived key |
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*/ |
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public function pbkdf2($algo, $password, $salt, $iterations, $length = 0) |
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{ |
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if (function_exists('hash_pbkdf2')) { |
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$outputKey = hash_pbkdf2($algo, $password, $salt, $iterations, $length, true); |
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if ($outputKey === false) { |
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throw new InvalidParamException('Invalid parameters to hash_pbkdf2()'); |
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} |
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return $outputKey; |
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} |
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// todo: is there a nice way to reduce the code repetition in hkdf() and pbkdf2()? |
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$test = @hash_hmac($algo, '', '', true); |
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if (!$test) { |
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throw new InvalidParamException('Failed to generate HMAC with hash algorithm: ' . $algo); |
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} |
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if (is_string($iterations) && preg_match('{^\d{1,16}$}', $iterations)) { |
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$iterations = (int) $iterations; |
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} |
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if (!is_integer($iterations) || $iterations < 1) { |
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throw new InvalidParamException('Invalid iterations'); |
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} |
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if (is_string($length) && preg_match('{^\d{1,16}$}', $length)) { |
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$length = (int) $length; |
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} |
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if (!is_integer($length) || $length < 0) { |
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throw new InvalidParamException('Invalid length'); |
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} |
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$hashLength = StringHelper::byteLength($test); |
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$blocks = $length !== 0 ? ceil($length / $hashLength) : 1; |
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$outputKey = ''; |
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for ($j = 1; $j <= $blocks; $j++) { |
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$hmac = hash_hmac($algo, $salt . pack('N', $j), $password, true); |
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$xorsum = $hmac; |
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for ($i = 1; $i < $iterations; $i++) { |
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$hmac = hash_hmac($algo, $hmac, $password, true); |
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$xorsum ^= $hmac; |
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} |
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$outputKey .= $xorsum; |
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} |
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if ($length !== 0) { |
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$outputKey = StringHelper::byteSubstr($outputKey, 0, $length); |
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} |
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return $outputKey; |
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} |
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/** |
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* Prefixes data with a keyed hash value so that it can later be detected if it is tampered. |
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* There is no need to hash inputs or outputs of [[encryptByKey()]] or [[encryptByPassword()]] |
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* as those methods perform the task. |
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* @param string $data the data to be protected |
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* @param string $key the secret key to be used for generating hash. Should be a secure |
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* cryptographic key. |
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* @param boolean $rawHash whether the generated hash value is in raw binary format. If false, lowercase |
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* hex digits will be generated. |
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* @throws InvalidConfigException |
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* @return string the data prefixed with the keyed hash |
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* @see validateData() |
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* @see generateRandomKey() |
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* @see hkdf() |
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* @see pbkdf2() |
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*/ |
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public function hashData($data, $key, $rawHash = false) |
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{ |
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$hash = hash_hmac(self::MAC_HASH, $data, $key, $rawHash); |
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if (!$hash) { |
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throw new InvalidConfigException('Failed to generate HMAC with hash algorithm: ' . self::MAC_HASH); |
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} |
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return $hash . $data; |
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} |
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/** |
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* Validates if the given data is tampered. |
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* @param string $data the data to be validated. The data must be previously |
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* generated by [[hashData()]]. |
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* @param string $key the secret key that was previously used to generate the hash for the data in [[hashData()]]. |
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* function to see the supported hashing algorithms on your system. This must be the same |
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* as the value passed to [[hashData()]] when generating the hash for the data. |
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* @param boolean $rawHash this should take the same value as when you generate the data using [[hashData()]]. |
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* It indicates whether the hash value in the data is in binary format. If false, it means the hash value consists |
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* of lowercase hex digits only. |
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* hex digits will be generated. |
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* @throws InvalidConfigException |
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* @return string the real data with the hash stripped off. False if the data is tampered. |
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* @see hashData() |
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*/ |
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public function validateData($data, $key, $rawHash = false) |
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{ |
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$test = @hash_hmac(self::MAC_HASH, '', '', $rawHash); |
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if (!$test) { |
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throw new InvalidConfigException('Failed to generate HMAC with hash algorithm: ' . self::MAC_HASH); |
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} |
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$hashLength = StringHelper::byteLength($test); |
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if (StringHelper::byteLength($data) >= $hashLength) { |
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$hash = StringHelper::byteSubstr($data, 0, $hashLength); |
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$pureData = StringHelper::byteSubstr($data, $hashLength, null); |
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$calculatedHash = hash_hmac(self::MAC_HASH, $pureData, $key, $rawHash); |
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if ($this->compareString($hash, $calculatedHash)) { |
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return $pureData; |
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} |
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} |
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return false; |
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} |
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/** |
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* Generates specified number of random bytes. |
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* Note that output may not be ASCII. |
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* @see generateRandomString() if you need a string. |
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* |
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* @param integer $length the number of bytes to generate |
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* @throws Exception on failure. |
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* @return string the generated random bytes |
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*/ |
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public function generateRandomKey($length = 32) |
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{ |
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if (!extension_loaded('mcrypt')) { |
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throw new InvalidConfigException('The mcrypt PHP extension is not installed.'); |
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} |
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$bytes = mcrypt_create_iv($length, MCRYPT_DEV_URANDOM); |
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if ($bytes === false) { |
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throw new Exception('Unable to generate random bytes.'); |
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} |
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return $bytes; |
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} |
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|
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/** |
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* Generates a random string of specified length. |
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* The string generated matches [A-Za-z0-9_-]+ and is transparent to URL-encoding. |
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* |
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* @param integer $length the length of the key in characters |
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* @throws Exception Exception on failure. |
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* @return string the generated random key |
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*/ |
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public function generateRandomString($length = 32) |
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{ |
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$bytes = $this->generateRandomKey($length); |
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// '=' character(s) returned by base64_encode() are always discarded because |
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// they are guaranteed to be after position $length in the base64_encode() output. |
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return strtr(substr(base64_encode($bytes), 0, $length), '+/', '_-'); |
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} |
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/** |
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* Generates a secure hash from a password and a random salt. |
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* |
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* The generated hash can be stored in database. |
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* Later when a password needs to be validated, the hash can be fetched and passed |
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* to [[validatePassword()]]. For example, |
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* |
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* ~~~ |
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* // generates the hash (usually done during user registration or when the password is changed) |
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* $hash = Yii::$app->getSecurity()->generatePasswordHash($password); |
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* // ...save $hash in database... |
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* |
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* // during login, validate if the password entered is correct using $hash fetched from database |
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* if (Yii::$app->getSecurity()->validatePassword($password, $hash) { |
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* // password is good |
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* } else { |
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* // password is bad |
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* } |
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* ~~~ |
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* |
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* @param string $password The password to be hashed. |
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* @param integer $cost Cost parameter used by the Blowfish hash algorithm. |
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* The higher the value of cost, |
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* the longer it takes to generate the hash and to verify a password against it. Higher cost |
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* therefore slows down a brute-force attack. For best protection against brute for attacks, |
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* set it to the highest value that is tolerable on production servers. The time taken to |
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* compute the hash doubles for every increment by one of $cost. |
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* @throws Exception on bad password parameter or cost parameter |
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* @throws InvalidConfigException |
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* @return string The password hash string. When [[passwordHashStrategy]] is set to 'crypt', |
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* the output is always 60 ASCII characters, when set to 'password_hash' the output length |
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* might increase in future versions of PHP (http://php.net/manual/en/function.password-hash.php) |
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* @see validatePassword() |
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*/ |
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public function generatePasswordHash($password, $cost = 13) |
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{ |
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switch ($this->passwordHashStrategy) { |
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case 'password_hash': |
|
if (!function_exists('password_hash')) { |
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throw new InvalidConfigException('Password hash key strategy "password_hash" requires PHP >= 5.5.0, either upgrade your environment or use another strategy.'); |
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} |
|
/** @noinspection PhpUndefinedConstantInspection */ |
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return password_hash($password, PASSWORD_DEFAULT, ['cost' => $cost]); |
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case 'crypt': |
|
$salt = $this->generateSalt($cost); |
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$hash = crypt($password, $salt); |
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// strlen() is safe since crypt() returns only ascii |
|
if (!is_string($hash) || strlen($hash) !== 60) { |
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throw new Exception('Unknown error occurred while generating hash.'); |
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} |
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return $hash; |
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default: |
|
throw new InvalidConfigException("Unknown password hash strategy '{$this->passwordHashStrategy}'"); |
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} |
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} |
|
|
|
/** |
|
* Verifies a password against a hash. |
|
* @param string $password The password to verify. |
|
* @param string $hash The hash to verify the password against. |
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* @return boolean whether the password is correct. |
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* @throws InvalidParamException on bad password or hash parameters or if crypt() with Blowfish hash is not available. |
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* @throws InvalidConfigException on unsupported password hash strategy is configured. |
|
* @see generatePasswordHash() |
|
*/ |
|
public function validatePassword($password, $hash) |
|
{ |
|
if (!is_string($password) || $password === '') { |
|
throw new InvalidParamException('Password must be a string and cannot be empty.'); |
|
} |
|
|
|
if (!preg_match('/^\$2[axy]\$(\d\d)\$[\.\/0-9A-Za-z]{22}/', $hash, $matches) || $matches[1] < 4 || $matches[1] > 30) { |
|
throw new InvalidParamException('Hash is invalid.'); |
|
} |
|
|
|
switch ($this->passwordHashStrategy) { |
|
case 'password_hash': |
|
if (!function_exists('password_verify')) { |
|
throw new InvalidConfigException('Password hash key strategy "password_hash" requires PHP >= 5.5.0, either upgrade your environment or use another strategy.'); |
|
} |
|
return password_verify($password, $hash); |
|
case 'crypt': |
|
$test = crypt($password, $hash); |
|
$n = strlen($test); |
|
if ($n !== 60) { |
|
return false; |
|
} |
|
return $this->compareString($test, $hash); |
|
default: |
|
throw new InvalidConfigException("Unknown password hash strategy '{$this->passwordHashStrategy}'"); |
|
} |
|
} |
|
|
|
/** |
|
* Generates a salt that can be used to generate a password hash. |
|
* |
|
* The PHP [crypt()](http://php.net/manual/en/function.crypt.php) built-in function |
|
* requires, for the Blowfish hash algorithm, a salt string in a specific format: |
|
* "$2a$", "$2x$" or "$2y$", a two digit cost parameter, "$", and 22 characters |
|
* from the alphabet "./0-9A-Za-z". |
|
* |
|
* @param integer $cost the cost parameter |
|
* @return string the random salt value. |
|
* @throws InvalidParamException if the cost parameter is not between 4 and 31 |
|
*/ |
|
protected function generateSalt($cost = 13) |
|
{ |
|
$cost = (int)$cost; |
|
if ($cost < 4 || $cost > 31) { |
|
throw new InvalidParamException('Cost must be between 4 and 31.'); |
|
} |
|
|
|
// Get a 20-byte random string |
|
$rand = $this->generateRandomKey(20); |
|
// Form the prefix that specifies Blowfish (bcrypt) algorithm and cost parameter. |
|
$salt = sprintf("$2y$%02d$", $cost); |
|
// Append the random salt data in the required base64 format. |
|
$salt .= str_replace('+', '.', substr(base64_encode($rand), 0, 22)); |
|
|
|
return $salt; |
|
} |
|
|
|
/** |
|
* Performs string comparison using timing attack resistant approach. |
|
* @see http://codereview.stackexchange.com/questions/13512 |
|
* @param string $expected string to compare. |
|
* @param string $actual user-supplied string. |
|
* @return boolean whether strings are equal. |
|
*/ |
|
public function compareString($expected, $actual) |
|
{ |
|
$expected .= "\0"; |
|
$actual .= "\0"; |
|
$expectedLength = StringHelper::byteLength($expected); |
|
$actualLength = StringHelper::byteLength($actual); |
|
$diff = $expectedLength - $actualLength; |
|
for ($i = 0; $i < $actualLength; $i++) { |
|
$diff |= (ord($actual[$i]) ^ ord($expected[$i % $expectedLength])); |
|
} |
|
return $diff === 0; |
|
} |
|
}
|
|
|