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<?php
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/**
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 * Random_* Compatibility Library
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 * for using the new PHP 7 random_* API in PHP 5 projects
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 *
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 * @version 2.0.10
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 * @released 2017-03-13
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 *
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 * The MIT License (MIT)
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 *
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 * Copyright (c) 2015 - 2017 Paragon Initiative Enterprises
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 *
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 * Permission is hereby granted, free of charge, to any person obtaining a copy
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 * of this software and associated documentation files (the "Software"), to deal
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 * in the Software without restriction, including without limitation the rights
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 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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 * copies of the Software, and to permit persons to whom the Software is
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 * furnished to do so, subject to the following conditions:
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 *
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 * The above copyright notice and this permission notice shall be included in
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 * all copies or substantial portions of the Software.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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 * SOFTWARE.
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 */
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if (!defined('PHP_VERSION_ID')) {
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    // This constant was introduced in PHP 5.2.7
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    $RandomCompatversion = array_map('intval', explode('.', PHP_VERSION));
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    define(
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        'PHP_VERSION_ID',
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        $RandomCompatversion[0] * 10000
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        + $RandomCompatversion[1] * 100
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        + $RandomCompatversion[2]
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    );
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    $RandomCompatversion = null;
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}
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/**
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 * PHP 7.0.0 and newer have these functions natively.
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 */
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if (PHP_VERSION_ID >= 70000) {
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    return;
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}
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if (!defined('RANDOM_COMPAT_READ_BUFFER')) {
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    define('RANDOM_COMPAT_READ_BUFFER', 8);
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}
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$RandomCompatDIR = dirname(__FILE__);
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require_once $RandomCompatDIR . '/byte_safe_strings.php';
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require_once $RandomCompatDIR . '/cast_to_int.php';
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require_once $RandomCompatDIR . '/error_polyfill.php';
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if (!is_callable('random_bytes')) {
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    /**
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     * PHP 5.2.0 - 5.6.x way to implement random_bytes()
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     *
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     * We use conditional statements here to define the function in accordance
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     * to the operating environment. It's a micro-optimization.
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     *
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     * In order of preference:
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     *   1. Use libsodium if available.
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     *   2. fread() /dev/urandom if available (never on Windows)
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     *   3. mcrypt_create_iv($bytes, MCRYPT_DEV_URANDOM)
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     *   4. COM('CAPICOM.Utilities.1')->GetRandom()
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     *
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     * See RATIONALE.md for our reasoning behind this particular order
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     */
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    if (extension_loaded('libsodium')) {
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        // See random_bytes_libsodium.php
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        if (PHP_VERSION_ID >= 50300 && is_callable('\\Sodium\\randombytes_buf')) {
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            require_once $RandomCompatDIR . '/random_bytes_libsodium.php';
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        } elseif (method_exists('Sodium', 'randombytes_buf')) {
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            require_once $RandomCompatDIR . '/random_bytes_libsodium_legacy.php';
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        }
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    }
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    /**
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     * Reading directly from /dev/urandom:
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     */
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    if (DIRECTORY_SEPARATOR === '/') {
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        // DIRECTORY_SEPARATOR === '/' on Unix-like OSes -- this is a fast
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        // way to exclude Windows.
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        $RandomCompatUrandom = true;
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        $RandomCompat_basedir = ini_get('open_basedir');
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        if (!empty($RandomCompat_basedir)) {
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            $RandomCompat_open_basedir = explode(
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                PATH_SEPARATOR,
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                strtolower($RandomCompat_basedir)
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            );
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            $RandomCompatUrandom = (array() !== array_intersect(
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                array('/dev', '/dev/', '/dev/urandom'),
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                $RandomCompat_open_basedir
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            ));
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            $RandomCompat_open_basedir = null;
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        }
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        if (
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            !is_callable('random_bytes')
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            &&
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            $RandomCompatUrandom
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            &&
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            @is_readable('/dev/urandom')
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        ) {
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            // Error suppression on is_readable() in case of an open_basedir
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            // or safe_mode failure. All we care about is whether or not we
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            // can read it at this point. If the PHP environment is going to
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            // panic over trying to see if the file can be read in the first
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            // place, that is not helpful to us here.
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            // See random_bytes_dev_urandom.php
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            require_once $RandomCompatDIR . '/random_bytes_dev_urandom.php';
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        }
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        // Unset variables after use
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        $RandomCompat_basedir = null;
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    } else {
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        $RandomCompatUrandom = false;
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    }
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    /**
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     * mcrypt_create_iv()
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     *
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     * We only want to use mcypt_create_iv() if:
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     *
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     * - random_bytes() hasn't already been defined
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     * - the mcrypt extensions is loaded
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     * - One of these two conditions is true:
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     *   - We're on Windows (DIRECTORY_SEPARATOR !== '/')
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     *   - We're not on Windows and /dev/urandom is readabale
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     *     (i.e. we're not in a chroot jail)
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     * - Special case:
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     *   - If we're not on Windows, but the PHP version is between
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     *     5.6.10 and 5.6.12, we don't want to use mcrypt. It will
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     *     hang indefinitely. This is bad.
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     *   - If we're on Windows, we want to use PHP >= 5.3.7 or else
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     *     we get insufficient entropy errors.
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     */
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    if (
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        !is_callable('random_bytes')
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        &&
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        // Windows on PHP < 5.3.7 is broken, but non-Windows is not known to be.
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        (DIRECTORY_SEPARATOR === '/' || PHP_VERSION_ID >= 50307)
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        &&
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        // Prevent this code from hanging indefinitely on non-Windows;
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        // see https://bugs.php.net/bug.php?id=69833
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        (
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            DIRECTORY_SEPARATOR !== '/' ||
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            (PHP_VERSION_ID <= 50609 || PHP_VERSION_ID >= 50613)
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        )
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        &&
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        extension_loaded('mcrypt')
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    ) {
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        // See random_bytes_mcrypt.php
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        require_once $RandomCompatDIR . '/random_bytes_mcrypt.php';
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    }
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    $RandomCompatUrandom = null;
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    /**
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     * This is a Windows-specific fallback, for when the mcrypt extension
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     * isn't loaded.
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     */
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    if (
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        !is_callable('random_bytes')
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        &&
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        extension_loaded('com_dotnet')
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        &&
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        class_exists('COM')
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    ) {
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        $RandomCompat_disabled_classes = preg_split(
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            '#\s*,\s*#',
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            strtolower(ini_get('disable_classes'))
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        );
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        if (!in_array('com', $RandomCompat_disabled_classes)) {
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            try {
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                $RandomCompatCOMtest = new COM('CAPICOM.Utilities.1');
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                if (method_exists($RandomCompatCOMtest, 'GetRandom')) {
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                    // See random_bytes_com_dotnet.php
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                    require_once $RandomCompatDIR . '/random_bytes_com_dotnet.php';
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                }
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            } catch (com_exception $e) {
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                // Don't try to use it.
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            }
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        }
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        $RandomCompat_disabled_classes = null;
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        $RandomCompatCOMtest = null;
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    }
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    /**
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     * throw new Exception
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     */
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    if (!is_callable('random_bytes')) {
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        /**
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         * We don't have any more options, so let's throw an exception right now
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         * and hope the developer won't let it fail silently.
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         *
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         * @param mixed $length
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         * @return void
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         * @throws Exception
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         */
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        function random_bytes($length)
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        {
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            unset($length); // Suppress "variable not used" warnings.
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            throw new Exception(
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                'There is no suitable CSPRNG installed on your system'
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            );
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        }
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    }
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}
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if (!is_callable('random_int')) {
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    require_once $RandomCompatDIR . '/random_int.php';
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}
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$RandomCompatDIR = null;
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