class User
{
    private $username = '';
    private $password = '';

    public function setPassword($password){
        $this->password = encript($password);
    }

    public function getPassword(){
       return $this->password;
    }

    function encript($data){
        return sha1($data);
    }
}

$this->password = encript($password);

$this->password = $this->encript($password);