<?php
/**
* Zend Framework (http://framework.zend.com/)
*
* @link http://github.com/zendframework/zf2 for the canonical source repository
* @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
*/
namespace Zend\Math\Source;
use RandomLib;
use SecurityLib\Strength;
/**
* Author:
* George Argyros <argyros.george@gmail.com>
*
* Copyright (c) 2012, George Argyros
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the <organization> nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL GEORGE ARGYROS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*
*
* The function is providing, at least at the systems tested :),
* $len bytes of entropy under any PHP installation or operating system.
* The execution time should be at most 10-20 ms in any system.
*
* Modified by Padraic Brady as part of Zend Framework to use 25% of the
* original version's iterations.
*/
class HashTiming implements RandomLib\Source
{
/**
* Return an instance of Strength indicating the strength of the source
*
* @return Strength An instance of one of the strength classes
*/
public static function getStrength()
{
return new Strength(Strength::VERYLOW);
}
/**
* Generate a random string of the specified size
*
* @param int $size The size of the requested random string
*
* @return string A string of the requested size
*/
public function generate($size)
{
$result = '';
$entropy = '';
$msec_per_round = 400;
$bits_per_round = 2;
$total = $size;
$bytes = 0;
$hash_length = 20;
$rounds = 0;
while (strlen($result) < $size) {
$bytes = ($total > $hash_length)? $hash_length : $total;
$total -= $bytes;
for ($i=1; $i < 3; $i++) {
$t1 = microtime(true);
$seed = mt_rand();
for ($j=1; $j < 50; $j++) {
$seed = sha1($seed);
}
$t2 = microtime(true);
$entropy .= $t1 . $t2;
}
$div = (int) (($t2 - $t1) * 1000000);
if ($div <= 0) {
$div = 400;
}
$rounds = (int) ($msec_per_round * 50 / $div);
$iter = $bytes * (int) (ceil(8 / $bits_per_round));
for ($i = 0; $i < $iter; $i ++) {
$t1 = microtime();
$seed = sha1(mt_rand());
for ($j = 0; $j < $rounds; $j++) {
$seed = sha1($seed);
}
$t2 = microtime();
$entropy .= $t1 . $t2;
}
$result .= sha1($entropy, true);
}
return substr($result, 0, $size);
}
}