[SOLVED] Is the connection between openhab servers and openhab cloud server safe?

Is the connection between openhab server and openhab cloud server safe?

I understand the browser access openhab cloud website by https.
But when we access openhab server remotely through openhab cloud server, there is connection between openhab cloud and openhab server.

Is this connection safe? In other words, is this connection is by https?
Can some expert shed some light? Thank you.

Take a look here.