//
// PassHash.php (Utility class):
//
class PassHash {  
      
        // blowfish  
        private static $algo = '$2a';  
      
        // cost parameter  
        private static $cost = '$10';  
      
      
        // mainly for internal use  
        public static function unique_salt() {  
            return substr(sha1(mt_rand()),0,22);  
        }  
      
        // this will be used to generate a hash  
        public static function hash($password) {  
      
            return crypt($password,  
                        self::$algo .  
                        self::$cost .  
                        '$' . self::unique_salt());  
      
        }  
      
      
        // this will be used to compare a password against a hash  
        public static function check_password($hash, $password) {  
      
            $full_salt = substr($hash, 0, 29);  
      
            $new_hash = crypt($password, $full_salt);  
      
            return ($hash == $new_hash);  
      
        }  
   
}



///////////////////////////////////////////////////////////////////
//
// Usage during registration (creating a new user record) :
//
///////////////////////////////////////////////////////////////////

// include the class  
require ("PassHash.php");  
      
// read all form input from $_POST  
// ...  
      
// do your regular form validation stuff  
// ...  
      
// hash the password  
$pass_hash = PassHash::hash($_POST['password']);  
      
// store all user info in the DB, excluding $_POST['password']  
// store $pass_hash instead  
// ...    



///////////////////////////////////////////////////////////////////
//
// Usage during login (checking the user record) :
//
///////////////////////////////////////////////////////////////////

// include the class  
require ("PassHash.php");  
      
// read all form input from $_POST  
// ...  
      
// fetch the user record based on $_POST['username']  or similar  
// ...  
      
// check the password the user tried to login with  
if (PassHash::check_password($user['pass_hash'], $_POST['password'])) {  
     // grant access  
     // ...  
} else {  
     // deny access  
     // ...  
}

//
// PassHash.php (Utility class):
//
class PassHash {  
      
        // blowfish  
        private static $algo = '$2a';  
      
        // cost parameter  
        private static $cost = '$10';  
      
      
        // mainly for internal use  
        public static function unique_salt() {  
            return substr(sha1(mt_rand()),0,22);  
        }  
      
        // this will be used to generate a hash  
        public static function hash($password) {  
      
            return crypt($password,  
                        self::$algo .  
                        self::$cost .  
                        '$' . self::unique_salt());  
      
        }  
      
      
        // this will be used to compare a password against a hash  
        public static function check_password($hash, $password) {  
      
            $full_salt = substr($hash, 0, 29);  
      
            $new_hash = crypt($password, $full_salt);  
      
            return ($hash == $new_hash);  
      
        }  
   
}



///////////////////////////////////////////////////////////////////
//
// Usage during registration (creating a new user record) :
//
///////////////////////////////////////////////////////////////////

// include the class  
require ("PassHash.php");  
      
// read all form input from $_POST  
// ...  
      
// do your regular form validation stuff  
// ...  
      
// hash the password  
$pass_hash = PassHash::hash($_POST['password']);  
      
// store all user info in the DB, excluding $_POST['password']  
// store $pass_hash instead  
// ...    



///////////////////////////////////////////////////////////////////
//
// Usage during login (checking the user record) :
//
///////////////////////////////////////////////////////////////////

// include the class  
require ("PassHash.php");  
      
// read all form input from $_POST  
// ...  
      
// fetch the user record based on $_POST['username']  or similar  
// ...  
      
// check the password the user tried to login with  
if (PassHash::check_password($user['pass_hash'], $_POST['password']) {  
     // grant access  
     // ...  
} else {  
     // deny access  
     // ...  
}

http://net.tutsplus.com/tutorials/php/understanding-hash-functions-and-keeping-passwords-safe/

Nice implementation of Blowfish for storing user passwords to prevent decryption when for example the user database is compromised. Origin: Burak Guzel@Nettuts

Password storing/checking class. Keeping passwords safe.

login, security

PHP