BCrypt

<?php
/**
 * BCrypt Library
 *
 * Password hashing library for HaKT Studios
 *
 * @author      Mark LaDoux
 * @copyright   Copyright © 2012 Mark LaDoux
 * @package     HaKT Studios
 * @subpackage  Security
 * @category    Hashing
 * @version     1.0.0
 */
 
class BCrypt
{
    /**
     * Random hashing level
     *
     * @access  protected
     * @static  int
     */
    protected static $rounds;
 
    /**
     * Class Constructor
     *
     * @access  public
     * @return  void
     */
    public function __construct()
    {
        self::$rounds = mt_rand(8, 32);
    }
 
    /**
     * Generate a hash from string
     *
     * @access  public
     * @param   string
     * @return  mixed   returns hash string on success, or FALSE on failure
     */
    public function generate($string)
    {
        // initialize salt
        $salt   = sprintf('$2a$%02d$', self::$rounds);
 
        // generate random bytes
        $bytes  = '';
 
        if( function_exists('openssl_random_pseudo_bytes')  &&
            (mb_strtoupper(mb_substr(PHP_OS, 0, 3)) !== 'WIN'))
        {
            $bytes = openssl_random_pseudo_bytes(16);
        }
 
        if( $bytes == ''                && 
            is_readable('/dev/urandom') &&
            ($fh = @fopen('/dev/urandom', 'rb')) !== FALSE)
        {
            $bytes = fread($fh, 16);
            fclose($fh);
        }
 
        if(mb_strlen($bytes, '8bit') < 16)
        {
            $bytes = '';
            $rstate = md5(microtime());
            if(function_exists('getmypid'))
            {
                $rstate .= getmypid();
            }
        }
 
        $bytes = mb_substr($bytes, 0, 16, '8bit');
 
        // encode bytes
        $itoa64 = './ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
        $enc_bytes = '';
        $i = 0;
 
        do
        {
            $c1         =   ord($bytes[$i++]);
            $enc_bytes  .=  $itoa64[$c1 >> 2];
            $c1         =   ($c1 & 0x03) << 4;
 
            if($i >= 16)
            {
                $enc_bytes .= $itoa64[$c1];
                break;
            }
 
            $c2         =   ord($enc_bytes[$i++]);
            $c1         |=  $c2 >> 6;
            $enc_bytes  .=  $itoa64[$c1];
            $enc_bytes  .= $itoa64[$c2 & 0x3f];
        } while(1);
 
        // create salt
        $salt .= $enc_bytes;
 
        // hash password
        $hash = crypt($string, $salt);
 
        // create output
        $output = (mb_strlen($hash) > 13) ? $hash : FALSE;
 
        // return output
        return $output;
    }
 
    /**
     * Verify string against a hash
     *
     * @access  public
     * @param   string  $string
     * @param   string  $hash
     * @return  bool
     */
    public function verify($string, $hash)
    {
        $output = (crypt($string, $hash) == $hash) ? TRUE : FALSE;
        return $output;
    }
}