Part-DB.Part-DB-server/src/Services/UserSystem/TFA/BackupCodeGenerator.php
2023-06-11 14:17:19 +02:00

81 lines
2.5 KiB
PHP

<?php
/**
* This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
*
* Copyright (C) 2019 - 2022 Jan Böhmer (https://github.com/jbtronics)
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published
* by the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* 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
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
declare(strict_types=1);
namespace App\Services\UserSystem\TFA;
use Exception;
use RuntimeException;
/**
* This class generates random backup codes for two-factor authentication.
*/
class BackupCodeGenerator
{
protected int $code_length;
/**
* BackupCodeGenerator constructor.
*
* @param int $code_length how many characters a single code should have
* @param int $code_count how many codes are generated for a whole backup set
*/
public function __construct(int $code_length, protected int $code_count)
{
if ($code_length > 32) {
throw new RuntimeException('Backup code can have maximum 32 digits!');
}
if ($code_length < 6) {
throw new RuntimeException('Code must have at least 6 digits to ensure security!');
}
$this->code_length = $code_length;
}
/**
* Generates a single backup code.
* It is a random hexadecimal value with the digit count configured in constructor.
*
* @return string The generated backup code (e.g. 1f3870be2)
*
* @throws Exception if no entropy source is available
*/
public function generateSingleCode(): string
{
$bytes = random_bytes(32);
return substr(md5($bytes), 0, $this->code_length);
}
/**
* Returns a full backup code set. The code count can be configured in the constructor.
*
* @return string[] an array containing different backup codes
*/
public function generateCodeSet(): array
{
$array = [];
for ($n = 0; $n < $this->code_count; ++$n) {
$array[] = $this->generateSingleCode();
}
return $array;
}
}