From: Jim McCoy <mccoy@ccwf.cc.utexas.edu>
Date: Tue, 1 Jun 93 09:35:14 PDT
To: ryan@rtfm.mlb.fl.us (RYAN Alan Porter)
Subject: Re: Crypto anarchy in a VW? (not the bug)
In-Reply-To: <Pine.3.03.9306010040.A26846-d100000@rtfm>
Message-ID: <199306011712.AA08151@ccwf.cc.utexas.edu>
MIME-Version: 1.0
Content-Type: text


Ryan Alan Porter <ryan@rtfm.mlb.fl.us> writes:
[...]
> An aside:  has anyone dealt with the concept of on-the-fly encryption for
> mass storage, kind of like the way the PCs can be 'stacked' or 'doubled'
> or whatever with on-the-fly compression?  I was thinking about trying to
> write some drivers for this for a 486 but I have never tried to write a
> device driver before and was wondering if anyone might have any suggestions.

Sort of.  I am still trying to work out a few design problems on a system
such as this for unix hosts.  At the moment it looks like I will be doing
this in linux but I still have a few issues to hammer out before I start
coding. 

>     1) these public key algorithms that we are working on are slow as
> balls, any idea if this would be feasable, given how PC users like to
> equate hard drive speed with penis size?

The PKE stuff would only need to handle the key management, so this could
conceivably be done in software.   The actual file encryption/decryption
must be done in hardware if you want to have any sort of speed at all.
This is actually the part I am still trying to figure out.  A research lab
in Switzerland designed a chip to do IDEA rather quickly, but I have still
not been able to get any information on how/when this might be marketed or
available outside the research lab (although I might be able to get one for
research purposes...)  Lacking an available IDEA chip I will have to use
DES (multi-pass or some other variant to get around the limits on DES
keyspace) in order to get the necessary throughput on the disk.

>     2) it seems that having your private key hanging around somewhere in
> memory the whole session would be horribly insecure, [...]

This I why I am hoping to use linux.  For those who don't know what linux
is, it is a fairly popular free unix for 386/486 intel machines.  With
linux I can start by burying the private key in the kernel during runtime
to give it some protection against snooping and hope to add a few kernel
hacks to make it a little more secure against examination.  Linux provides
a dos emulator for those who need PC programs and unix/x11/whatever for the
rest of us...

Such a system would not be completely secure but would provide some
protection for files, which is more than they get now...

jim