[Security] TLS Certificates Verification (summary)

[Dave Cridland]

On Wed Aug 20 07:37:32 2008, Johansson Olle E wrote:
> 1) XMPP often uses (and the XMPP foundation strongly recommends)  
> TLS  between client and server. Within server, the messages are in  
> the  clear. Thus, it gives no secure channel between two end  
> points. Also,  between two endpoints connecting to servers with  
> TLS, there could be a  non-TLS connection server-to-server (S2S).  
> So even with a TLS  connection between a client and a server, we  
> can't assume that we have  security end-to-end. We need to set that  
> up. This discussion is about  how to set up confidential and  
> authenticated client-to-client  sessions, based on the this  
> scenario.

Right, good summary.

> 3) Clients may be behind NAT, so even a client-to-client direct   
> session may need help from a server (proxy). This will have to be   
> considered.

This is a non-issue - we have Jingle, so we have the ability to  
negotiate various channels, at least one of which (IBB) will work  
through any amount of NATs and firewalling, albeit at a cost of  
efficiency and ugliness. Really, this whole debate about IBB vs NATs  
vs whatever is immaterial; we have Jingle specifically to solve all  
these problems, and it passes the buck to ICE-TCP et al to solve the  
tricky cases.

> 5) Not all clients are human. We need solutions, but maybe not one   
> solution, for
>     - human clients on some sort of computer
>     - bots with a delegation from a human (set-top-boxes)
>     - applications (XMPP is used as middleware)

For reasons concerning the retention of my santity, at least, I'd  
prefer these to be as common as possible.

Dave.
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