From: aba@dcs.exeter.ac.uk
Date: Wed, 19 Jul 95 11:32:29 PDT
To: cypherpunks@toad.com
Subject: ANNOUNCE: bruteRC4, 40 bits all swept
Message-ID: <29518.9507191827@exe.dcs.exeter.ac.uk>
MIME-Version: 1.0
Content-Type: text/plain



Well we have demonstrated that 40 bit RC4 can be brute forced in
around a weeks compute time.

(We've also learned a list of thinks to fix for the next attempt as no
key was forthcoming :-|, details on why not and what is being fixed to
ensure this doesn't happen with a future RC4-40 or with the coming
40+88 SSL brute forceing are given below)

The problems are logistic, human error, etc, from a compute time point
of view it *really* was a full sweep of a 40 bit keyspace.  And on
average you would expect to sweep in half this time.

The bulk of the work was done in under one weeks compute time, but
problems with people forgetting to acknowledge what they swept, meant
that 3 or 4 people swept the remaining key space over, which slowed
down this announce.

Here's the hall of fame, for bits/percentage swept per identifiable
contributer (this is tallied by acknowledgement, if you swept but did
not acknoweldge quickly enough or at all, that work won't show as the
last keyspace was re-swept to hurry things up.  The first
acknowledgement to be recieved counts, the rest get ignored).

bits/40   percent  contributer
----------------------------------------------------------------------
37.2 bits (14.063%) Jon Shekter <jshekter@alias.com>
36.4 bits (8.081%) Alvin Brattli <alvin@phys.uit.no>
36.1 bits (6.909%) anonymous
36.1 bits (6.836%) Dan Bailey <merzbow@ibm.net>
36.1 bits (6.812%) Piete Brooks <Piete.Brooks@cl.cam.ac.uk>
35.6 bits (4.688%) Loren Rittle <rittle@comm.mot.com>
35.6 bits (4.663%) Adam Back <aba@dcs.ex.ac.uk>
35.4 bits (4.102%) Eric Young <eay@mincom.oz.au>
35.4 bits (4.004%) Fred <admin@dcwill.com>
35.3 bits (3.809%) Martin Hamilton <martin@mrrl.lut.ac.uk>
35.2 bits (3.711%) Kevin Wang <kwang@blackbox.punk.net>
35.0 bits (3.125%) Richard Martin <rmartin@alias.com>
34.7 bits (2.490%) Dan Oelke <droelke@aud.alcatel.com>
34.3 bits (1.978%) Branko Lankester
34.0 bits (1.611%) Simon McAuliffe <sai@comp.vuw.ac.nz>
34.0 bits (1.562%) Mike Gebis <m-gebis@uiuc.edu>
33.8 bits (1.392%) Pat Finerty <zinc@zifi.genetics.utah.edu>
33.8 bits (1.367%) <hodgeman@csd.uwm.edu>
33.5 bits (1.123%) Panu Rissanen <Panu.Rissanen@lut.fi>
33.4 bits (1.001%) Paul Bell <pjb@23kgroup.com>
33.3 bits (0.977%) Matt Thomlinson <phantom@u.washington.edu>
33.3 bits (0.952%) Will Kinney <kinney@colorado.edu>
33.2 bits (0.903%) T J Hardin <hardin@cyberspace.com>
33.2 bits (0.879%) Patrick May <pjm@ionia.engr.sgi.com>
32.8 bits (0.684%) Stephane Bortzmeyer <bortzmeyer@cnam.fr>
32.7 bits (0.635%) anonner
32.5 bits (0.537%) Matt Pauker <mpauker@peganet.com>
32.5 bits (0.537%) Ed Kern <ejk@digex.net>
32.5 bits (0.537%) Andrew Kuchling <andrewk@cst.ca>
32.5 bits (0.537%) <rmtodd@mailhost.ecn.uoknor.edu>
32.4 bits (0.513%) <somogyi@digmedia.com>
32.3 bits (0.488%) Jon Baber <jbaber@mi.leeds.ac.uk>
32.2 bits (0.439%) Bryce Boland <bryce@cybernet.co.nz>
32.0 bits (0.391%) Thad Beier <thad@thresher.uucp.netcom.com>
32.0 bits (0.391%) Per Stoltze <stoltze@fysik.dtu.dk>
32.0 bits (0.391%) Glenn Powers <gpowers@bradley.edu>
32.0 bits (0.391%) <janzen@idacom.hp.com>
31.8 bits (0.342%) Mike Bailey <bailey@computek.net>
31.7 bits (0.317%) Robert Hayden <hayden@krypton.mankato.msus.edu>
31.7 bits (0.317%) John Limpert <johnl@radix.net>
31.6 bits (0.293%) Opus
31.6 bits (0.293%) Mark Rogaski <rogaski@phobos.lib.iup.edu>
31.6 bits (0.293%) <josh@silicon.net>
31.5 bits (0.269%) Michael Bacon <mbacon@dfw.net>
31.3 bits (0.244%) Jim Gillogly <jim@acm.org>
31.3 bits (0.244%) David Zuhn <zoo@armadillo.com>
31.2 bits (0.220%) Russell Ross <rross@sci.dixie.edu>
31.2 bits (0.220%) Don Kitchen <don@cs.byu.edu>
31.0 bits (0.195%) Scott Renfro <csylvix!srenfro@cuok.cameron.edu>
31.0 bits (0.195%) Planar <Damien.Doligez@inria.fr>
30.8 bits (0.171%) Matt <panzer@dhp.com>
30.8 bits (0.171%) Joe Thomas <jthomas@access.digex.net>
30.8 bits (0.171%) Adrian Thomson <a.thomson@nexor.co.uk>
30.6 bits (0.146%) Michael Axelrod <mja@cacs.usl.edu>
30.6 bits (0.146%) Mark Eichin <mark@kitten.gen.ma.us>
30.6 bits (0.146%) Jason Burrell <jburrell@crl.com>
30.3 bits (0.122%) Will Ware <wware@world.std.com>
30.3 bits (0.122%) Kevin Maher <kmaher@ucsd.edu>
30.3 bits (0.122%) Josh Sled <jsled@cello.gina.calstate.edu>
30.3 bits (0.122%) Checkered Daemon <cdaemon@goblin.punk.net>
30.3 bits (0.122%) Andrew Roos <andrewr@realtime.co.za>
30.0 bits (0.098%) Jason Weisberger <jweis@primenet.com>
30.0 bits (0.098%) <pdlamb@iquest.com>
30.0 bits (0.098%) <matt@comp.vuw.ac.nz>
29.6 bits (0.073%) Mark Grant <mark@unicorn.com>
29.6 bits (0.073%) Lou Poppler <lwp@mail.msen.com>
29.6 bits (0.073%) Edwin de Graaf <graaf@iaehv.nl>
29.6 bits (0.073%) David Conrad <conrad@detroit.freenet.org>
29.6 bits (0.073%) Dan Tauber <dat@netcom.com>
29.6 bits (0.073%) Alexandra Griffin <acg@kzin.cen.ufl.edu>
29.6 bits (0.073%) <pkronenw@erc.cat.syr.edu>
29.6 bits (0.073%) <ghazelwo@cs.oberlin.edu>
29.0 bits (0.049%) Stuart <stu@nemesis.wimsey.com>
29.0 bits (0.049%) Pekka Riiali <Pekka.Riiali@lut.fi>
29.0 bits (0.049%) Jeffrey Ollie <jeffo@noc.netins.net>
29.0 bits (0.049%) James Hightower <jamesh@netcom.com>
29.0 bits (0.049%) Hadmut Danisch <danisch@ira.uka.de>
29.0 bits (0.049%) Bob Snyder <rsnyder@janet.advsys.com>
29.0 bits (0.049%) <stevet@smeg.net4.io.org>
28.0 bits (0.024%) Sang Hahn <sghahn@math1.kaist.ac.kr>
28.0 bits (0.024%) Roy Silvernail <roy@cybrspc.mn.org>
28.0 bits (0.024%) Ollivier Robert <roberto@keltia.freenix.fr>
28.0 bits (0.024%) Lucky Green <shamrock@netcom.com>
28.0 bits (0.024%) L Futplex McCarthy <futplex@pseudonym.com>
28.0 bits (0.024%) Jeff Licquia <jalicqui@prairienet.org>
28.0 bits (0.024%) J Francois <frenchie@magus.dgsys.com>
28.0 bits (0.024%) Brian LaMacchia <bal@mit.edu>
28.0 bits (0.024%) Andy Brown <a.brown@nexor.co.uk>
28.0 bits (0.024%) Adam Morrison <adam@math.tau.ac.il>
28.0 bits (0.024%) <mikew@nersc.gov>
----------------------------------------------------------------------
40.0 bits (100.000%) 89 cpunks + x * anonners in 1 weeks compute


Report is on the brute-rc4.html page also:

	http://dcs.ex.ac.uk/~aba/brute-rc4.html


Problems.
---------

But, briefly these are the things which may be responsible for the
failure to find a key:

a) We weren't sure if we had a known plaintext / ciphertext pair

   This due to lack of Microsoft Access specs, this was known from 
   the begining, but we thought we'd try it and see.

b) Eeek! There was a bug in bruterc4.c for some time which affected
   Alphas, and possibly other BSD machines.  This meant keyspace 
   wasn't being searched when the -v option was used.

c) Some people reported that their browser / uuencode software
   combination meant that cutting and pasting of the uuencode plain
   text and cipher text files was silently failing due to extra spaces
   inserted by a flawed pasting operation.

d) Human error - it is possible that some keys were unswept - by 
   accident.

e) Malicious humans - we don't know, but think this was not a problem.


Solutions.
----------

Proposed solutions for future brute forcing efforts (such as the
upcoming SSL effort), for respective points above:


a) Need better spec of MA, or more experimentation / reverse
   engineering.

   For SSL this is not a problem as the SSL specs are openly available
   and very detailed.

b) Write bug free software :-)  Test more rigourously on multiple unixs
   and architectures with a brief test run.

c) Use hex numbers in a config file.  Ie don't use uuencode on web page.

d) We're going to have the programs (bruteRC4.c and bruteSSL.c) produce
   a checksum on completion.  Acknowledgements of swept keyspace must be
   with checksum.  Crude check to reduce chances of mistyped big hex nums.
   
   Represent the key space as a 4 digit hex number like this: 1a23, in
   terms of 24 bit keyspaces, and represent keyspace to sweep in terms
   of numbers of those, lots of people had difficulty reasoning in log
   base2 for bits.

e) Do nothing yet.  If we get lots of compute and it proves to be a
   problem perhaps implement some redundancy into the system.


Coming soon brute force attempt on Hal Finney's brute of 40+88bit SSL.
Watch this space, several cypherpunks are hard at work optimising
their bruteSSL.c code, and also writing farming software via a system
of servers connected via sockets.  The WWW page doler will still be
available for those with out direct IP.

Hal Finney's SSL challenge is here:

	http://www.portal.com/~hfinney/sslchal.html

More on SSL later, but we hoped to give the SSL one a wider announce
in sci.crypt, and see how *fast* we can brute 40 bit keyspace.

Hope to see your compute in the brute SSL effort when it is announced,

Adam
--
HAVE *YOU* EXPORTED A CRYPTO SYSTEM TODAY? --> http://dcs.ex.ac.uk/~aba/rsa/
--rsa--------------------------------8<-------------------------------------
#!/usr/local/bin/perl -s-- -export-a-crypto-system-sig -RSA-in-3-lines-PERL
($k,$n)=@ARGV;$m=unpack(H.$w,$m."\0"x$w),$_=`echo "16do$w 2+4Oi0$d*-^1[d2%
Sa2/d0<X+d*La1=z\U$n%0]SX$k"[$m*]\EszlXx++p|dc`,s/^.|\W//g,print pack('H*'
,$_)while read(STDIN,$m,($w=2*$d-1+length($n||die"$0 [-d] k n\n")&~1)/2)
-------------------------------------8<-------------------------------------
TRY: echo squeamish ossifrage | rsa -e 3 7537d365 | rsa -d 4e243e33 7537d365