[Interest] Security thoughts on Webchannel

[Jason H]

...
> Is there any possibility to register new objects on an existing channel?
> I would like to use a first registered object for user  
> authentification and a second one, that is registered after success of  
> the first operation.

I don't know what you mean "register new objects on an existing channel".
I have made Qt clients that received JSON over websockets to implement private and group chat.
The server used a combination of technologies, including websockets and redis. This was done in a HIPAA-compliant manner. (So secure enough). Websockets is just an asynchronous transport mechanism, as opposed to request-response. 
I think you are more asking about general application architecture. I can't really advise on that either. But I will say that I did however find some short-comings in Qt's implementation which have since been addressed. As it stands, I would not hesitate to use Qt's websockets, provided you think websockets are the way to go.