Thomas Steffen wrote: > > Dan Stromberg <[EMAIL PROTECTED]> writes: > > > Unless the default for X connections became "encrypt > ^^^^^^ > > Even that would not help *present* X terminal users :-) > You have to modify the X terminal, there is absolutely no other way. > > >>> Would this mean a modification to the X server and Xlib? > >> > >> Yes, both, obviously. > > > > ... > > Both sides are connection via a byte channel abstraction (pipe, TCP/IP > connection, stream, whatever). If you want to encrypt the data going > over the pipe, you have to change both sides.
IPsec provides encryption and authentication at the IP layer, protecting everything running above it. If your "X terminal" runs Linux, get the IPsec from www.freeswan.org. I believe all the *BSDs now include IPsec, and Sun and HP offer it for their Unices, though I'm not sure if it is built in or an optional extra on those. That does not solve the problem for a true X terminal, but even there using IPsec might be the way to go. My guess would be that some X terminals would suffer an X performance loss because of the overheads of encryption. Some estimates of those overheads, for Linux IPsec, are at: http://www.freeswan.org/freeswan_trees/freeswan-1.94/doc/performance.html The bulk of those overheads are for packet-level encryption. They should be similar for IPsec and SSH, though there might be differences in other areas. > > I'm not that worried about MITM attacks, Methinks you should be. > > The other guy had it right - it has to be a no brainer, and work on > > a true X terminal. It's going to require some sort of software upgrade to the terminal, whether you put crypto into the X libs, use SSH or use IPsec. That means you need either co-operation from a vendor or an X terminal with an open development environment. Do you have either? > What about getting ssh included into the X terminal? I guess there are > problem with xdm, but appart from that I cannot see what you could > gain by including encryption in X. Nor I. To do any network crypto well enough that people can rely on it you need both well-analysed crypto primitives (lots of those around) and a well-analysed cryptographic network protocol (a big, tricky undetaking). SSH meets those criteria, is easily supported on the host end, might not be too hard on the terminal end, and is adequate for this task. It is the obvious simple solution. IPsec also meets the criteria and is more general and flexible than SSH. However, it is a bigger implementation project and it is not clear that the generality pays off in this application. SSL/TLS also meets the criteria. I don't see offhand how it could be applied to this problem, but there is probably a way. Trying to build crypto into X strikes me as re-inventing the wheel, with a risk of having it come out square. _______________________________________________ Xpert mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/xpert
