Subject: Re: Ian's Xkernel
To: Gordon W. Ross <>
From: Curt Sampson <>
List: port-sun3
Date: 04/11/1997 14:20:51
On Fri, 11 Apr 1997, der Mouse wrote:

> >> The hostid is not secret, because the last part of the ethernet
> >> address IS the last three bytes of the hostid, and [...]
> > By default this is the case, but the hostid is relatively easy to
> > change in most cases.
> If you're prepared to pull the idprom, you might as well pull the other
> ROMs and put in ones with real crypto code.  I was trying to design a
> mechanism that would work for stock hardware.

I don't recall if this is the case for Sun 3s, but on Sun 4c models,
at least, you can change the hostid and Ethernet address to anything
you like from the monitor.

Regardless, there's plenty of other room in the eprom to put a
secret key, such as the area reserved for the custom boot message.

However, assuming we're happy to serve any X terminal that happens
to be on the network (as I am), would we not get most of what we
want if we just had the X terminal generate a random session key
on boot, encrypt it with the server's public key, and hand it to
the server? This ensure that that particular session is secure. It
would not prevent spoofing of the server, but I could live with
that, since that's pretty hard to do unless someone has access to
your network.


Curt Sampson		Info at
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