278 lines
7.2 KiB
PHP
278 lines
7.2 KiB
PHP
<?php
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/**
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* @package FOF
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* @copyright Copyright (c)2010-2021 Nicholas K. Dionysopoulos / Akeeba Ltd
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* @license GNU General Public License version 2, or later
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*/
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namespace FOF30\Encrypt;
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defined('_JEXEC') || die;
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use FOF30\Encrypt\AesAdapter\AdapterInterface;
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use FOF30\Encrypt\AesAdapter\OpenSSL;
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use FOF30\Utils\Phpfunc;
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/**
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* A simple abstraction to AES encryption
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*
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* Usage:
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*
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* // Create a new instance. The key is ignored – only use it if you have legacy encrypted content you need to decrypt
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* $aes = new Aes('ignored');
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* // Set the password. Do not use uf you have legacy encrypted content you need to decrypt
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* $aes->setPassword('yourRealPassword');
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* // Encrypt something.
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* $cipherText = $aes->encryptString($sourcePlainText);
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* // Decrypt something
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* $plainText = $aes->decryptString($sourceCipherText);
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*/
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class Aes
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{
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/**
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* The cipher key.
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*
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* @var string
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*/
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private $key = '';
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/**
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* The AES encryption adapter in use.
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*
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* @var AdapterInterface
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*/
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private $adapter;
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/**
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* Initialise the AES encryption object.
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*
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* Note: If the key is not 16 bytes this class will do a stupid key expansion for legacy reasons (produce the
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* SHA-256 of the key string and throw away half of it).
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*
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* @param string $key The encryption key (password). It can be a raw key (16 bytes) or a passphrase.
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* @param int $strength Bit strength (128, 192 or 256) – ALWAYS USE 128 BITS. THIS PARAMETER IS DEPRECATED.
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* @param string $mode Encryption mode. Can be ebc or cbc. We recommend using cbc.
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* @param Phpfunc $phpfunc For testing
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*/
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public function __construct($key, $strength = 128, $mode = 'cbc', Phpfunc $phpfunc = null)
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{
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$this->adapter = new OpenSSL();
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if (!$this->adapter->isSupported($phpfunc))
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{
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throw new \RuntimeException('Your server does not have the PHP OpenSSL extension enabled. This is required for encryption handling.');
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}
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$this->adapter->setEncryptionMode($mode, $strength);
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$this->setPassword($key, true);
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}
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/**
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* Is AES encryption supported by this PHP installation?
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*
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* @return boolean
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*/
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public static function isSupported(Phpfunc $phpfunc = null)
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{
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if (!is_object($phpfunc) || !($phpfunc instanceof $phpfunc))
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{
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$phpfunc = new Phpfunc();
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}
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$adapter = new OpenSSL();
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if (!$adapter->isSupported($phpfunc))
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{
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return false;
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}
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if (!$phpfunc->function_exists('base64_encode'))
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{
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return false;
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}
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if (!$phpfunc->function_exists('base64_decode'))
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{
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return false;
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}
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if (!$phpfunc->function_exists('hash_algos'))
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{
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return false;
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}
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$algorightms = $phpfunc->hash_algos();
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if (!in_array('sha256', $algorightms))
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{
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return false;
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}
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return true;
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}
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/**
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* Sets the password for this instance.
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*
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* WARNING: Do not use the legacy mode, it's insecure
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*
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* @param string $password The password (either user-provided password or binary encryption key) to use
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* @param bool $legacyMode True to use the legacy key expansion. We recommend against using it.
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*/
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public function setPassword($password, $legacyMode = false)
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{
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$this->key = $password;
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$passLength = strlen($password);
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if (function_exists('mb_strlen'))
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{
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$passLength = mb_strlen($password, 'ASCII');
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}
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// Legacy mode was doing something stupid, requiring a key of 32 bytes. DO NOT USE LEGACY MODE!
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if ($legacyMode && ($passLength != 32))
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{
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// Legacy mode: use the sha256 of the password
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$this->key = hash('sha256', $password, true);
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// We have to trim or zero pad the password (we end up throwing half of it away in Rijndael-128 / AES...)
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$this->key = $this->adapter->resizeKey($this->key, $this->adapter->getBlockSize());
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}
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}
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/**
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* Encrypts a string using AES
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*
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* @param string $stringToEncrypt The plaintext to encrypt
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* @param bool $base64encoded Should I Base64-encode the result?
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*
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* @return string The cryptotext. Please note that the first 16 bytes of
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* the raw string is the IV (initialisation vector) which
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* is necessary for decoding the string.
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*/
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public function encryptString($stringToEncrypt, $base64encoded = true)
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{
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$blockSize = $this->adapter->getBlockSize();
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$randVal = new Randval();
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$iv = $randVal->generate($blockSize);
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$key = $this->getExpandedKey($blockSize, $iv);
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$cipherText = $this->adapter->encrypt($stringToEncrypt, $key, $iv);
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// Optionally pass the result through Base64 encoding
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if ($base64encoded)
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{
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$cipherText = base64_encode($cipherText);
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}
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// Return the result
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return $cipherText;
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}
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/**
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* Decrypts a ciphertext into a plaintext string using AES
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*
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* @param string $stringToDecrypt The ciphertext to decrypt. The first 16 bytes of the raw string must contain
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* the IV (initialisation vector).
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* @param bool $base64encoded Should I Base64-decode the data before decryption?
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*
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* @return string The plain text string
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*/
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public function decryptString($stringToDecrypt, $base64encoded = true)
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{
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if ($base64encoded)
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{
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$stringToDecrypt = base64_decode($stringToDecrypt);
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}
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// Extract IV
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$iv_size = $this->adapter->getBlockSize();
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$iv = substr($stringToDecrypt, 0, $iv_size);
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$key = $this->getExpandedKey($iv_size, $iv);
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// Decrypt the data
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$plainText = $this->adapter->decrypt($stringToDecrypt, $key);
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return $plainText;
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}
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/**
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* @param $blockSize
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* @param $iv
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*
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* @return string
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*/
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public function getExpandedKey($blockSize, $iv)
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{
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$key = $this->key;
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$passLength = strlen($key);
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if (function_exists('mb_strlen'))
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{
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$passLength = mb_strlen($key, 'ASCII');
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}
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if ($passLength != $blockSize)
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{
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$iterations = 1000;
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$salt = $this->adapter->resizeKey($iv, 16);
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$key = hash_pbkdf2('sha256', $this->key, $salt, $iterations, $blockSize, true);
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}
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return $key;
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}
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}
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if (!function_exists('hash_pbkdf2'))
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{
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function hash_pbkdf2($algo, $password, $salt, $count, $length = 0, $raw_output = false)
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{
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if (!in_array(strtolower($algo), hash_algos()))
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{
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trigger_error(__FUNCTION__ . '(): Unknown hashing algorithm: ' . $algo, E_USER_WARNING);
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}
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if (!is_numeric($count))
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{
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trigger_error(__FUNCTION__ . '(): expects parameter 4 to be long, ' . gettype($count) . ' given', E_USER_WARNING);
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}
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if (!is_numeric($length))
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{
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trigger_error(__FUNCTION__ . '(): expects parameter 5 to be long, ' . gettype($length) . ' given', E_USER_WARNING);
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}
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if ($count <= 0)
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{
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trigger_error(__FUNCTION__ . '(): Iterations must be a positive integer: ' . $count, E_USER_WARNING);
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}
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if ($length < 0)
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{
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trigger_error(__FUNCTION__ . '(): Length must be greater than or equal to 0: ' . $length, E_USER_WARNING);
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}
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$output = '';
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$block_count = $length ? ceil($length / strlen(hash($algo, '', $raw_output))) : 1;
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for ($i = 1; $i <= $block_count; $i++)
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{
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$last = $xorsum = hash_hmac($algo, $salt . pack('N', $i), $password, true);
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for ($j = 1; $j < $count; $j++)
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{
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$xorsum ^= ($last = hash_hmac($algo, $last, $password, true));
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}
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$output .= $xorsum;
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}
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if (!$raw_output)
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{
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$output = bin2hex($output);
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}
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return $length ? substr($output, 0, $length) : $output;
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}
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}
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