For example, it is possible to setup up a secure private docker registry, but does portainer support that as well?
I wondered this myself too. According to https://github.com/portainer/portainer/issues/679 Portainer does not currently support SSL/TLS. You will need to setup a reverse proxy to do this.
@030 @adrianfalleiro yup, at the moment there is no native support for SSL inside Portainer. You need to use a reverse-proxy.
Note that I've re-open #679 as a feature request.
@adrianfalleiro @deviantony PR created