miniMVC/sys/libraries/Bcrypt.php

<?php
/**
 * MiniMVC
 *
 * Convention-based micro-framework for PHP
 *
 * @package		miniMVC
 * @author 		Timothy J. Warren
 * @copyright	Copyright (c) 2011 - 2012
 * @link 		https://github.com/aviat4ion/miniMVC
 * @license 	http://philsturgeon.co.uk/code/dbad-license
 */

// --------------------------------------------------------------------------

/**
 * Class to simplify dealing with bcrypt for password handling
 *
 * @see
 * @package miniMVC
 * @subpackage libraries
 */
class Bcrypt {

	/**
	 * Number of times to recurse
	 *
	 * @var int
	 */
	private $rounds;

	/**
	 * Stores random seed
	 *
	 * @var mixed
	 */
	private $randomState;

	/**
	 * Create a new Bcrypt object
	 *
	 * @param int $rounds
	 */
	public function __construct($rounds = 12)
	{
		if (CRYPT_BLOWFISH != 1)
		{
			throw new Exception("bcrypt not supported in this installation. See http://php.net/crypt");
		}

		$this->rounds = $rounds;
	}

	// --------------------------------------------------------------------------

	/**
	 * Returns a has for the input string
	 *
	 * @param string
	 * @return string
	 */
	public function hash($input)
	{
		$hash = crypt($input, $this->getSalt());

		if (strlen($hash) > 13)
			return $hash;

		return false;
	}

	// --------------------------------------------------------------------------

	/**
	 * Check if a password hash is valid
	 *
	 * @param string
	 * @param string
	 * @return bool
	 */
	public function verify($input, $existingHash)
	{
		$hash = crypt($input, $existingHash);

		return $hash === $existingHash;
	}

	// --------------------------------------------------------------------------

	/**
	 * Private function to generate the random salt
	 *
	 * @return string
	 */
	private function getSalt()
	{
		$salt = sprintf('$2a$%02d$', $this->rounds);

		$bytes = $this->getRandomBytes(16);

		$salt .= $this->encodeBytes($bytes);

		return $salt;
	}

	// --------------------------------------------------------------------------

	/**
	 * Private method to generate random characters for salt
	 *
	 * @param int
	 * @return string
	 */
	private function getRandomBytes($count)
	{
		$bytes = '';

		if (function_exists('openssl_random_pseudo_bytes') && (strtoupper(substr(PHP_OS, 0, 3)) !== 'WIN')) // OpenSSL slow on Win
		{
			$bytes = openssl_random_pseudo_bytes($count);
		}

		if ($bytes === '' && is_readable('/dev/urandom') && ($hRand = @fopen('/dev/urandom', 'rb')) !== FALSE)
		{
			$bytes = fread($hRand, $count);
			fclose($hRand);
		}

		if (strlen($bytes) < $count)
		{
			$bytes = '';

			if ($this->randomState === null)
			{
				$this->randomState = microtime();
				if (function_exists('getmypid'))
				{
					$this->randomState .= getmypid();
				}
			}

			for ($i = 0; $i < $count; $i += 16)
			{
				$this->randomState = md5(microtime() . $this->randomState);

				if (PHP_VERSION >= '5')
				{
					$bytes .= md5($this->randomState, true);
				}
				else
				{
					$bytes .= pack('H*', md5($this->randomState));
				}
			}

			$bytes = substr($bytes, 0, $count);
		}

		return $bytes;
	}

	// --------------------------------------------------------------------------

	/**
	 * Further randomizes salt?
	 *
	 * @param string
	 * @return string
	 */
	private function encodeBytes($input)
	{
		// The following is code from the PHP Password Hashing Framework
		$itoa64 = './ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';

		$output = '';
		$i = 0;
		do
		{
			$c1 = ord($input[$i++]);
			$output .= $itoa64[$c1 >> 2];
			$c1 = ($c1 & 0x03) << 4;
			if ($i >= 16)
			{
				$output .= $itoa64[$c1];
				break;
			}

			$c2 = ord($input[$i++]);
			$c1 |= $c2 >> 4;
			$output .= $itoa64[$c1];
			$c1 = ($c2 & 0x0f) << 2;

			$c2 = ord($input[$i++]);
			$c1 |= $c2 >> 6;
			$output .= $itoa64[$c1];
			$output .= $itoa64[$c2 & 0x3f];
		} while (1);

		return $output;
	}
}