Bcrypt.php

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');

/**
* Bcrypt Class
* Simple and easy to use bcrypt helper for Codeigniter
*
* @author 		Waldir Bertazzi Junior
* @link 		http://waldir.org/
*/

class Bcrypt {
	private $times;
	private $random_state;
	
	function __construct($times = 12){
		$this->CI =& get_instance();
		$this->times = $times;
	}
	
	/**
	 * Hashes a input using bcrypt.
	 *
	 * @param String input string to be hashed
	 * @return String contains hashed input
	 * @author Waldir Bertazzi Junior
	**/	
	public function hash($input){
		$hash = crypt($input, $this->generate_salt());
		
		// hashed successful
		if(strlen($hash) > 13)
			return $hash;
		
		// hash failed.
		return false;
	}
	
	/**
	* Function that compares the input with the correspondent hash. The same input should return the same hash.
	* Return true if the input is the same as the hashed input.
	*
	* @param String input string without hash
	* @param String previous hashed string
	* @return Boolean
	* @author Waldir Bertazzi Junior
	**/
	public function compare($input, $hashed_string) {
		$hash = crypt($input, $hashed_string);
		
		// return if the hashed string is the same
		return $hash === $hashed_string;
	}
	
	
	private function generate_salt(){
		$salt = sprintf('$2a$%02d$', $this->times);
		
		// generate random bytes for our salt
		$bytes = $this->get_random_bytes(16);
		
		$salt .= $this->encode_bytes($bytes);
		
		return $salt;
	}
	
	/**
	* Function that return random bytes from various sources.
	*
	* @return		random bytes
	* @param		number of bytes to generate
	* @author		Waldir Bertazzi Junior
	**/
	private function get_random_bytes($count){
		$bytes = '';
		
		if(function_exists('openssl_random_pseudo_bytes') && !(PHP_OS == 'Windows' || PHP_OS == 'WIN32' || PHP_OS == 'WINNT')) {
			$bytes = openssl_random_pseudo_bytes($count);
		}
		
		if($bytes === '' && is_readable('/dev/urandom') && ($h_rand = @fopen('/dev/urandom', 'rb')) !== false){
			$bytes = fread($h_rand, $count);
			fclose($h_rand);
		}
		
		if(strlen($bytes) < $count) {
			$bytes = '';
			
			if($this->random_state === null) {
				$this->random_state = microtime();
				if(function_exists('getmypid')) {
					$this->random_state .= getmypid();
				}
			}
		
		
			for($i = 0; $i < $count; $i += 16) {
				$this->random_state = md5(microtime() . $this->random_state);
				if (PHP_VERSION >= '5') {
					$bytes .= md5($this->random_state, true);
				} else {
					$bytes .= pack('H*', md5($this->random_state));
				}
			}

			$bytes = substr($bytes, 0, $count);
		}
		
		return $bytes;
	}
	
	/**
	* Function taken from PHP Password Hashing Framework
	*
	* @return void
	* @author PHP Password Hashing Framework
	* @link http://www.openwall.com/phpass/
	**/
	private function encode_bytes($input){
		$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;
	}
	
}
?>