Re: The Upcoming DES Challenge

At 06:56 PM 1/6/97 -0800, Mike Duvos wrote:
>Peter Trei (trei@process.com) writes:
>
>Ick.  Why overly complexify things?  A known plaintext attack
>would be far more straightforward.  After all, the goal is to
>recover the key, not the message.  Having to find a key which
>decrypts to something having all high bits clear will discourage
>people who might want to take a crack at this independent of the
>canned program you are going to distribute.

I agree. A real life crack of DES can almost always assume a know plain
text. Why should the demo crack take the 10% hit?

>[snip]
>
> > It will NOT run as a screen saver.
>
>Too bad.  The screensaver paradigm is something the unwashed
>masses can easily understand.

I have been running the distributed prime search software (see my .sig) for
about two months now. [2^1398269-1 is prime!] If you haven't tried this
software, I'd urge you to do so now. Not only because it might make you
famous, but because it will give you some ideas how a distributed DES crack
might work.

I always liked the screen saver idea, but a crack using screen savers only
works while the screen saver is active. The mersenne prime program runs on
the lowest priority thread under Win95/NT/Linux. It works even while you
are working, using all the idle cycles it can find, while at the same time
having no effect at all on any of the work you do. Install it and forget
about it. It's better than a screen saver.



-- Lucky Green <mailto:shamrock@netcom.com> PGP encrypted mail preferred
   Make your mark in the history of mathematics. Use the spare cycles of
   your PC/PPC/UNIX box to help find a new prime.
   http://www.mersenne.org/prime.htm

> > > It will NOT run as a screen saver.
> >
> >Too bad.  The screensaver paradigm is something the unwashed
> >masses can easily understand.
> 
> I have been running the distributed prime search software (see my .sig) for
> about two months now. [2^1398269-1 is prime!] If you haven't tried this
> software, I'd urge you to do so now. Not only because it might make you
> famous, but because it will give you some ideas how a distributed DES crack
> might work.
> 
> I always liked the screen saver idea, but a crack using screen savers only
> works while the screen saver is active. The mersenne prime program runs on
> the lowest priority thread under Win95/NT/Linux. It works even while you
> are working, using all the idle cycles it can find, while at the same time
> having no effect at all on any of the work you do. Install it and forget
> about it. It's better than a screen saver.

I agree with Lucky. It may not be as easy for the great unwashed to comprehend, but 
the low-pri thread is the best way to go to maximize cpu time on the project. I too 
am running the Mersenne software on my system (and 5 others), but that project will 
go on hold once a stable version of the DES cracker is available. 

Btw: the person implementing the software may want to take a look at the software 
the GIMPS search is using. It is simple, yet effective.

amp


------------------------
Name: amp
E-mail: amp@pobox.com
Date: 01/07/97
Time: 06:51:34
Visit http://www.public-action.com/SkyWriter/WacoMuseum

EARTH FIRST! We'll strip mine the other planets later.
------------------------

>    Make your mark in the history of mathematics. Use the spare cycles of
>    your PC/PPC/UNIX box to help find a new prime.
>    http://www.mersenne.org/prime.htm

This .sig and the DES challenge gave me an idea that I'd like to 
bounce off the list.

One of the things about these screensaver style cracking/searching
programs is the hassle in downloading/installing the programs.
There's also the problem of maybe downloading some trojan.  And
they need to be changed any time there's a new problem or key
to work on (or a bug). The whole thing is so cumbersome that
it's easy to claim it's not really a practical attack, or that
it costs too much.

However, what if there was a safe scripting language with bignum
arithmetic and other cryptographic primitives, and what if
lots of people ran a service that would accept scripts in 
that language and respond with the answer?  Say, a Safe-TCL 
interface to Peter Gutmann's cryptlib, running at idle 
priority?  Sort of like a distributed batch queue, and also 
a bit like the way jobs are (were?) submitted to Crays.  The 
Cypherpunks Super Computer. It need not be significantly slower 
than raw code if the primitives are high level enough.

I think this would be technically quite interesting, and would
maybe play well in the media too.  In response to the "it would 
cost too much to be _really_ practical" claim, anyone could always 
note that there was this distributed cypherpunks supercomputer 
that anonymous people could use to break keys with for free.

I'd be happy to code something like this up if there's interest.

Comments?

Cheers,
Frank O'Dwyer.

"Frank O'Dwyer" <fod@brd.ie> writes:

> However, what if there was a safe scripting language with bignum
> arithmetic and other cryptographic primitives, and what if
> lots of people ran a service that would accept scripts in 
> that language and respond with the answer?  Say, a Safe-TCL 
> interface to Peter Gutmann's cryptlib, running at idle 
> priority?  Sort of like a distributed batch queue, and also 
> a bit like the way jobs are (were?) submitted to Crays.  The 
> Cypherpunks Super Computer. It need not be significantly slower 
> than raw code if the primitives are high level enough.

Perl 5.0 has a better, simpler, safety mode than Java (and probably Safe-TCL
too), and runs on more machines.  It is also the standard for CGI, so anyone
already running CGI could simply add a perl-based crypto service.

Dave