PrivateBin/lib/serversalt.php

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<?php
/**
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* PrivateBin
*
* a zero-knowledge paste bin
*
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* @link https://github.com/PrivateBin/PrivateBin
* @copyright 2012 Sébastien SAUVAGE (sebsauvage.net)
* @license https://www.opensource.org/licenses/zlib-license.php The zlib/libpng License
* @version 0.22
*/
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namespace PrivateBin;
use Exception;
/**
* serversalt
*
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* This is a random string which is unique to each PrivateBin installation.
* It is automatically created if not present.
*
* Salt is used:
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* - to generate unique VizHash in discussions (which are not reproductible across PrivateBin servers)
* - to generate unique deletion token (which are not re-usable across PrivateBin servers)
*/
class serversalt extends persistence
{
/**
* generated salt
*
* @access private
* @static
* @var string
*/
private static $_salt = '';
/**
* generate a large random hexadecimal salt
*
* @access public
* @static
* @return string
*/
public static function generate()
{
$randomSalt = '';
if (function_exists('mcrypt_create_iv')) {
$randomSalt = bin2hex(mcrypt_create_iv(256, MCRYPT_DEV_URANDOM));
} else {
// fallback to mt_rand()
for ($i = 0; $i < 256; ++$i) {
$randomSalt .= base_convert(mt_rand(), 10, 16);
}
}
return $randomSalt;
}
/**
* get server salt
*
* @access public
* @static
* @throws Exception
* @return string
*/
public static function get()
{
if (strlen(self::$_salt)) {
return self::$_salt;
}
$file = 'salt.php';
if (self::_exists($file)) {
$items = explode('|', @file_get_contents(self::getPath($file)));
if (!is_array($items) || count($items) != 3) {
throw new Exception('unable to read file ' . self::getPath($file), 20);
}
self::$_salt = $items[1];
} else {
self::$_salt = self::generate();
self::_store(
$file,
'<?php /* |'. self::$_salt . '| */ ?>'
);
}
return self::$_salt;
}
/**
* set the path
*
* @access public
* @static
* @param string $path
* @return void
*/
public static function setPath($path)
{
self::$_salt = '';
parent::setPath($path);
}
}