Cross site request forgery (CSRF) Protection in PHP

Class Security
{
    public static function getToken()
    {
        $token = sha1(uniqid());
        $_SESSION['token'] = $token;
        return $_SESSION['token'];
    }

    public static function checkToken($token)
    {
        if (isset($_SESSION['token'])) {
            if ($token == $_SESSION['token']) {
                unset($_SESSION['token']);
                return true;
            }
        }

        return false;
    }
}