<?php
/**
* Random_* Compatibility Library
* for using the new PHP 7 random_* API in PHP 5 projects
*
* The MIT License (MIT)
*
* Copyright (c) 2015 - 2018 Paragon Initiative Enterprises
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
if (!is_callable('random_bytes')) {
/**
* Windows with PHP < 5.3.0 will not have the function
* openssl_random_pseudo_bytes() available, so let's use
* CAPICOM to work around this deficiency.
*
* @param int $bytes
*
* @throws Exception
*
* @return string
*/
function random_bytes($bytes)
{
try {
/** @var int $bytes */
$bytes = RandomCompat_intval($bytes);
} catch (TypeError $ex) {
throw new TypeError(
'random_bytes(): $bytes must be an integer'
);
}
if ($bytes < 1) {
throw new Error(
'Length must be greater than 0'
);
}
/** @var string $buf */
$buf = '';
if (!class_exists('COM')) {
throw new Error(
'COM does not exist'
);
}
/** @var COM $util */
$util = new COM('CAPICOM.Utilities.1');
$execCount = 0;
/**
* Let's not let it loop forever. If we run N times and fail to
* get N bytes of random data, then CAPICOM has failed us.
*/
do {
$buf .= base64_decode((string) $util->GetRandom($bytes, 0));
if (RandomCompat_strlen($buf) >= $bytes) {
/**
* Return our random entropy buffer here:
*/
return (string) RandomCompat_substr($buf, 0, $bytes);
}
++$execCount;
} while ($execCount < $bytes);
/**
* If we reach here, PHP has failed us.
*/
throw new Exception(
'Could not gather sufficient random data'
);
}
}
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