<?php
/*
Copyright (c) 2009-2014 F3::Factory/Bong Cosca, All rights reserved.
This file is part of the Fat-Free Framework (http://fatfree.sf.net).
THE SOFTWARE AND DOCUMENTATION ARE PROVIDED "AS IS" WITHOUT WARRANTY OF
ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR
PURPOSE.
Please see the license.txt file for more information.
*/
//! Lightweight password hashing library
class Bcrypt extends Prefab {
//@{ Error messages
const
E_CostArg='Invalid cost parameter',
E_SaltArg='Salt must be at least 22 alphanumeric characters';
//@}
//! Default cost
const
COST=10;
/**
* Generate bcrypt hash of string
* @return string|FALSE
* @param $pw string
* @param $salt string
* @param $cost int
**/
function hash($pw,$salt=NULL,$cost=self::COST) {
if ($cost<4 || $cost>31)
user_error(self::E_CostArg);
$len=22;
if ($salt) {
if (!preg_match('/^[[:alnum:]\.\/]{'.$len.',}$/',$salt))
user_error(self::E_SaltArg);
}
else {
$raw=16;
$iv='';
if (extension_loaded('mcrypt'))
$iv=mcrypt_create_iv($raw,MCRYPT_DEV_URANDOM);
if (!$iv && extension_loaded('openssl'))
$iv=openssl_random_pseudo_bytes($raw);
if (!$iv)
for ($i=0;$i<$raw;$i++)
$iv.=chr(mt_rand(0,255));
$salt=str_replace('+','.',base64_encode($iv));
}
$salt=substr($salt,0,$len);
$hash=crypt($pw,sprintf('$2y$%02d$',$cost).$salt);
return strlen($hash)>13?$hash:FALSE;
}
/**
* Check if password is still strong enough
* @return bool
* @param $hash string
* @param $cost int
**/
function needs_rehash($hash,$cost=self::COST) {
list($pwcost)=sscanf($hash,"$2y$%d$");
return $pwcost<$cost;
}
/**
* Verify password against hash using timing attack resistant approach
* @return bool
* @param $pw string
* @param $hash string
**/
function verify($pw,$hash) {
$val=crypt($pw,$hash);
$len=strlen($val);
if ($len!=strlen($hash) || $len<14)
return FALSE;
$out=0;
for ($i=0;$i<$len;$i++)
$out|=(ord($val[$i])^ord($hash[$i]));
return $out===0;
}
}
