controller
    public function register()
    {
            $register = User::create(array(
                'username' => 'test1',
                'password' => 'testpass'
            ));

            $register->re_password = 'testpass';

            if($register->is_valid())
            {
                echo 'Login';
            }
            else
            {
                print_r($register->errors->full_messages());
            }

    }


Model
<?php
class User extends ActiveRecord\Model
{
    var $password = FALSE;
    var $re_password = FALSE;

    static $validates_presence_of = array(
        array('username'),
        array('password')
    );

    static $validates_size_of = array(
        array('username', 'within' => array(3,15)),
        array('password', 'minimum' => 6)
    );

    public function validate()
    {
        if($this->password != $this->re_password && $this->re_password != $this->password)
        {

            echo $this->password;


            $this->errors->add('Password', "and retype password must me be the same.");
        }
    }

    function before_save()
    {
        if($this->password)
        {
            $this->hashed_password = $this->hash_password($this->password);
        }
    }

    private function hash_password($password)
    {
        $salt = bin2hex(mcrypt_create_iv(32, MCRYPT_DEV_URANDOM));
        $hash = hash('sha256', $salt . $password);

        return $salt . $hash;
    }'