I study a little bit the plugin structure and was able to create a two-factor authentication.
But sadly I need a little bit help.
If I manually add my secret and a var, which say if the user use a two-factor authentication, then everything works, but I'm not able to create the form (as I would like to have it) in ISPConfig3.
So if there is someone who is able to create some forms with database entrys and updates then please PN me.
I hope there will be a response soon, so that we can release the two-factor-authentication together.
Greetings from Germany,
There is also a picture which show the 2-factor-auth (don't worry - I use a special theme for my ispconfig)