nextcloud/lib/private/security/securerandom.php

93 lines
2.8 KiB
PHP

<?php
/**
* @author Lukas Reschke <lukas@owncloud.com>
* @author Morris Jobke <hey@morrisjobke.de>
*
* @copyright Copyright (c) 2015, ownCloud, Inc.
* @license AGPL-3.0
*
* This code is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License, version 3,
* along with this program. If not, see <http://www.gnu.org/licenses/>
*
*/
namespace OC\Security;
use RandomLib;
use Sabre\DAV\Exception;
use OCP\Security\ISecureRandom;
/**
* Class SecureRandom provides a layer around RandomLib to generate
* secure random strings.
*
* Usage:
* \OC::$server->getSecureRandom()->getMediumStrengthGenerator()->generate(10);
*
* @package OC\Security
*/
class SecureRandom implements ISecureRandom {
/** @var \RandomLib\Factory */
var $factory;
/** @var \RandomLib\Generator */
var $generator;
function __construct() {
$this->factory = new RandomLib\Factory;
}
/**
* Convenience method to get a low strength random number generator.
*
* Low Strength should be used anywhere that random strings are needed
* in a non-cryptographical setting. They are not strong enough to be
* used as keys or salts. They are however useful for one-time use tokens.
*
* @return $this
*/
public function getLowStrengthGenerator() {
$this->generator = $this->factory->getLowStrengthGenerator();
return $this;
}
/**
* Convenience method to get a medium strength random number generator.
*
* Medium Strength should be used for most needs of a cryptographic nature.
* They are strong enough to be used as keys and salts. However, they do
* take some time and resources to generate, so they should not be over-used
*
* @return $this
*/
public function getMediumStrengthGenerator() {
$this->generator = $this->factory->getMediumStrengthGenerator();
return $this;
}
/**
* Generate a random string of specified length.
* @param string $length The length of the generated string
* @param string $characters An optional list of characters to use if no characterlist is
* specified all valid base64 characters are used.
* @return string
* @throws \Exception If the generator is not initialized.
*/
public function generate($length, $characters = '') {
if(is_null($this->generator)) {
throw new \Exception('Generator is not initialized.');
}
return $this->generator->generateString($length, $characters);
}
}