@classmethod
def validate_security(cls, app, ssl_options=None):
    """Check the application's security.

        Show messages, or abort if necessary, based on the security configuration.
        """
    if not app.ip:
        warning = (
            'WARNING: The Jupyter server is listening on all IP addresses')
        if ssl_options is None:
            app.log.warning(warning +
                ' and not using encryption. This is not recommended.')
        if not app.password and not app.token:
            app.log.warning(warning +
                ' and not using authentication. This is highly insecure and not recommended.'
                )
    elif not app.password and not app.token:
        app.log.warning(
            'All authentication is disabled.  Anyone who can connect to this server will be able to run code.'
            )
