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658 lines
28 KiB
PHP
658 lines
28 KiB
PHP
<?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 'OpenSSL' PHP extension for random key/string gneration on Windows and
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* for encryption/decryption on all platforms. 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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* Block cipher algorithm for encryption and decryption.
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*/
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const BLOCK_CIPHER = 'AES';
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/**
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* Block cipher operation mode.
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*/
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const BLOCK_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 $passwordHashStrategy = 'crypt';
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/**
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* Encrypts data using a password.
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* Derives keys for encryption and authentication from the password using PBKDF2 and a random salt,
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* which is deliberately slow to protect against dictionary attacks. Use [[encryptByKey()]] to
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* encrypt fast using a cryptographic key rather than a password. Key derivation time is
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* determined by [[$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 compromised 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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* Returns a string for use in the $method argument of openssl_en/decrypt functions.
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*
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* No checks are made. This function will produce nonsense that OpenSSL will reject
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* if the cipher is not AES, the key size is not 16, 24 or 32, or if the mode is
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* unsupported.
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*
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* Tbh, this is a foot gun. But we need it if we allow the user to change key size
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* or block mode. And the user must override it top use a cipher other than AES.
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*
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* @return string OpenSSL cipher method.
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*/
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protected function opensslCipher()
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{
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return static::BLOCK_CIPHER . '-' . (8 * static::KEY_SIZE) . '-' . static::BLOCK_MODE;
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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 boolean $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, $info)
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{
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$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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$ivSize = 16;
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$iv = $this->generateRandomKey($ivSize);
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$encrypted = openssl_encrypt($data, $this->opensslCipher(), $key, OPENSSL_ZERO_PADDING, $iv);
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$encrypted = base64_decode($encrypted);
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$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 16, i.e. the AES block 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 boolean $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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$ivSize = 16;
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$iv = StringHelper::byteSubstr($data, 0, $ivSize);
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$encrypted = base64_encode(StringHelper::byteSubstr($data, $ivSize, null));
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$decrypted = openssl_decrypt($encrypted, $this->opensslCipher(), $key, OPENSSL_ZERO_PADDING, $iv);
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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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$blockSize = 16;
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$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 integer $length length of the output key in bytes. If 0, the output key is
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* the length of the hash algorithm output.
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* @throws InvalidParamException when HMAC generation fails.
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* @return string the derived key
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*/
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public function hkdf($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 integer $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 integer $length length of the output key in bytes. If 0, the output key is
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* the length of the hash algorithm output.
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* @return string the derived key
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* @throws InvalidParamException when hash generation fails due to invalid params given.
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*/
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public function pbkdf2($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 $rawHash whether the generated hash value is in raw binary format. If false, lowercase
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* hex digits will be generated.
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* @return string the data prefixed with the keyed hash
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* @throws InvalidConfigException when HMAC generation fails.
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* @see validateData()
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* @see generateRandomKey()
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* @see hkdf()
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* @see pbkdf2()
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*/
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public function hashData($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 $rawHash this should take the same value as when you generate the data using [[hashData()]].
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* It indicates whether the hash value in the data is in binary format. If false, it means the hash value consists
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* of lowercase hex digits only.
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* hex digits will be generated.
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* @return string the real data with the hash stripped off. False if the data is tampered.
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* @throws InvalidConfigException when HMAC generation fails.
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* @see hashData()
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*/
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public function validateData($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 $length the number of bytes to generate
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* @return string the generated random bytes
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* @throws InvalidConfigException if OpenSSL extension is required (e.g. on Windows) but not installed.
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* @throws Exception on failure.
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*/
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public function generateRandomKey($length = 32)
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{
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/*
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* Strategy
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*
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* The most common platform is Linux, on which /dev/urandom is the best choice. Many other OSs
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* implement a device called /dev/urandom for Linux compat and it is good too. So if there is
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* a /dev/urandom then it is our first choice regardless of OS.
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*
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* Nearly all other modern Unix-like systems (the BSDs, Unixes and OS X) have a /dev/random
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* that is a good choice. If we didn't get bytes from /dev/urandom then we try this next but
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* only if the system is not Linux. Do not try to read /dev/random on Linux.
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*
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* Finally, OpenSSL can supply CSPR bytes. It is our last resort. On Windows this reads from
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* CryptGenRandom, which is the right thing to do. On other systems that don't have a Unix-like
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* /dev/u?random , it will deliver bytes from its own CSPRNG that is seeded from kernel sources
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* of randomness. Even though it is fast, we don't generally prefer OpenSSL over /dev/u?random
|
|
* because an RNG in user space memory is undesirable.
|
|
*
|
|
* For background, see http://sockpuppet.org/blog/2014/02/25/safely-generate-random-numbers/
|
|
*/
|
|
|
|
$bytes = '';
|
|
|
|
// If we are on Linux or any OS that mimics the Linux /dev/urandom device, e.g. FreeBSD or OS X,
|
|
// then read from /dev/urandom.
|
|
if (file_exists('/dev/urandom')) {
|
|
$handle = fopen('/dev/urandom', 'r');
|
|
if ($handle !== false) {
|
|
$bytes .= fread($handle, $length);
|
|
fclose($handle);
|
|
}
|
|
}
|
|
|
|
if (mb_strlen($bytes, '8bit') >= $length) {
|
|
return mb_substr($bytes, 0, $length, '8bit');
|
|
}
|
|
|
|
// If we are not on Linux and there is a /dev/random device then we have a BSD or Unix device
|
|
// that won't block. It's not safe to read from /dev/random on Linux.
|
|
if (php_uname('s') !== 'Linux' && file_exists('/dev/random')) {
|
|
$handle = fopen('/dev/random', 'r');
|
|
if ($handle !== false) {
|
|
$bytes .= fread($handle, $length);
|
|
fclose($handle);
|
|
}
|
|
}
|
|
|
|
if (mb_strlen($bytes, '8bit') >= $length) {
|
|
return mb_substr($bytes, 0, $length, '8bit');
|
|
}
|
|
|
|
if (!extension_loaded('openssl')) {
|
|
throw new InvalidConfigException('The OpenSSL PHP extension is not installed.');
|
|
}
|
|
|
|
$bytes .= openssl_random_pseudo_bytes($length, $cryptoStrong);
|
|
|
|
if (mb_strlen($bytes, '8bit') < $length || !$cryptoStrong) {
|
|
throw new Exception('Unable to generate random bytes.');
|
|
}
|
|
|
|
return mb_substr($bytes, 0, $length, '8bit');
|
|
}
|
|
|
|
/**
|
|
* Generates a random string of specified length.
|
|
* The string generated matches [A-Za-z0-9_-]+ and is transparent to URL-encoding.
|
|
*
|
|
* @param integer $length the length of the key in characters
|
|
* @return string the generated random key
|
|
* @throws InvalidConfigException if OpenSSL extension is needed but not installed.
|
|
* @throws Exception on failure.
|
|
*/
|
|
public function generateRandomString($length = 32)
|
|
{
|
|
$bytes = $this->generateRandomKey($length);
|
|
// '=' character(s) returned by base64_encode() are always discarded because
|
|
// they are guaranteed to be after position $length in the base64_encode() output.
|
|
return strtr(substr(base64_encode($bytes), 0, $length), '+/', '_-');
|
|
}
|
|
|
|
/**
|
|
* Generates a secure hash from a password and a random salt.
|
|
*
|
|
* The generated hash can be stored in database.
|
|
* Later when a password needs to be validated, the hash can be fetched and passed
|
|
* to [[validatePassword()]]. For example,
|
|
*
|
|
* ~~~
|
|
* // generates the hash (usually done during user registration or when the password is changed)
|
|
* $hash = Yii::$app->getSecurity()->generatePasswordHash($password);
|
|
* // ...save $hash in database...
|
|
*
|
|
* // during login, validate if the password entered is correct using $hash fetched from database
|
|
* if (Yii::$app->getSecurity()->validatePassword($password, $hash) {
|
|
* // password is good
|
|
* } else {
|
|
* // password is bad
|
|
* }
|
|
* ~~~
|
|
*
|
|
* @param string $password The password to be hashed.
|
|
* @param integer $cost Cost parameter used by the Blowfish hash algorithm.
|
|
* The higher the value of cost,
|
|
* the longer it takes to generate the hash and to verify a password against it. Higher cost
|
|
* therefore slows down a brute-force attack. For best protection against brute for attacks,
|
|
* set it to the highest value that is tolerable on production servers. The time taken to
|
|
* compute the hash doubles for every increment by one of $cost.
|
|
* @return string The password hash string. When [[passwordHashStrategy]] is set to 'crypt',
|
|
* the output is always 60 ASCII characters, when set to 'password_hash' the output length
|
|
* might increase in future versions of PHP (http://php.net/manual/en/function.password-hash.php)
|
|
* @throws Exception on bad password parameter or cost parameter.
|
|
* @throws InvalidConfigException when an unsupported password hash strategy is configured.
|
|
* @see validatePassword()
|
|
*/
|
|
public function generatePasswordHash($password, $cost = 13)
|
|
{
|
|
switch ($this->passwordHashStrategy) {
|
|
case 'password_hash':
|
|
if (!function_exists('password_hash')) {
|
|
throw new InvalidConfigException('Password hash key strategy "password_hash" requires PHP >= 5.5.0, either upgrade your environment or use another strategy.');
|
|
}
|
|
/** @noinspection PhpUndefinedConstantInspection */
|
|
return password_hash($password, PASSWORD_DEFAULT, ['cost' => $cost]);
|
|
case 'crypt':
|
|
$salt = $this->generateSalt($cost);
|
|
$hash = crypt($password, $salt);
|
|
// strlen() is safe since crypt() returns only ascii
|
|
if (!is_string($hash) || strlen($hash) !== 60) {
|
|
throw new Exception('Unknown error occurred while generating hash.');
|
|
}
|
|
return $hash;
|
|
default:
|
|
throw new InvalidConfigException("Unknown password hash strategy '{$this->passwordHashStrategy}'");
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Verifies a password against a hash.
|
|
* @param string $password The password to verify.
|
|
* @param string $hash The hash to verify the password against.
|
|
* @return boolean whether the password is correct.
|
|
* @throws InvalidParamException on bad password or hash parameters or if crypt() with Blowfish hash is not available.
|
|
* @throws InvalidConfigException when an unsupported password hash strategy is configured.
|
|
* @see generatePasswordHash()
|
|
*/
|
|
public function validatePassword($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 $cost the cost parameter
|
|
* @return string the random salt value.
|
|
* @throws InvalidParamException if the cost parameter is out of the range of 4 to 31.
|
|
*/
|
|
protected function generateSalt($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;
|
|
}
|
|
}
|