Re: DES-Busting Screen Savers?
Tim and others have discussed the effectiveness of random search vs. centralized servers, problems of cheating, scaling, etc. My take is that, if you can ignore scaling, the best approach is probably to have a central server that doles out keyspace and wraps around when it reaches 100%, and doesn't worry too much about collecting results - even if there are cheaters, machine failures, etc., and people don't finish their keyspace, it'll be more likely to cover the whole space than randoms. (Make it a web page, and use cut&paste to transfer to the search programs so they don't need to be network-equipped.) To support scaling, make it easy for people to run subset servers; grab a chunk of keyspace from the main server and dole it out to people who ask you for it. If you want to get fancy, hack a DNS server to allow people to register their machines as NNN.descrack.org, 0<=NNN<1000, so that people can find subsets without having to ask the main server.
a brute force "screen saver" for
-- By the time the total amount of computons expended has equalled the amount that would have been expended in a "no duplications" allocated search, the Poisson probability distribution says that 1/e = 36.8% of the keyspace will not have been searched; the rest of the probabilty lies in keyspace searched once, twice, three times, etc.
# Thanks; Bill # Bill Stewart +1-415-442-2215 stewarts@ix.netcom.com # http://www.idiom.com/~wcs # Confuse Authority!
-----BEGIN PGP SIGNED MESSAGE----- On Wed, 24 Jul 1996, Bill Stewart wrote:
Date: Wed, 24 Jul 1996 02:24:58 -0700 From: Bill Stewart <stewarts@ix.netcom.com> To: cypherpunks@toad.com Subject: Re: DES-Busting Screen Savers?
Tim and others have discussed the effectiveness of random search vs. centralized servers, problems of cheating, scaling, etc. My take is that, if you can ignore scaling, the best approach is probably to have a central server that doles out keyspace and wraps around when it reaches 100%, and doesn't worry too much about collecting results - even if there are cheaters, machine failures, etc., and people don't finish their keyspace, it'll be more likely to cover the whole space than randoms. (Make it a web page, and use cut&paste to transfer to the search programs so they don't need to be network-equipped.)
Agreed. Also, we might want to keep the plaintext on, say, a floppy disk, as to discourage the recovery technique (which, admitidly, is easier than actually cracking the key). I might suggest, also, to put the disks in the hands of someone who has little or no reason to help. Sadly, the best person for the job that _I_ can think of would have to be "Dr." Dave.
To support scaling, make it easy for people to run subset servers; grab a chunk of keyspace from the main server and dole it out to people who ask you for it. If you want to get fancy, hack a DNS server to allow people to register their machines as NNN.descrack.org, 0<=NNN<1000, so that people can find subsets without having to ask the main server.
Or hack it to use a 56 bit IP netmask-ish thing, and keep track of keys that way (i'm not endorsing this idea, just pointing it out) --Deviant "I understand by 'freedom of Spirit' something quite definite - the unconditional will to say No, where it is dangerous to say No. Friedrich Nietzsche -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQEVAwUBMfb/oTAJap8fyDMVAQFBAQf8DV1YEpKvyVp6zrotThJ7YMjcFIsJnq+g /myED4a4KgB6TmArFnPocQlCQXMyKo6KNKupYzyHppINWgkftrKBFgh1Uu3zVL3e r0K9lsf55XVyEVLUdu1lKOJX4Thh+9NePXjF7SrMXAMR/3czvUs+NqDs8wMzkiPX lLYV+9WVJFR7J+rLtonL2V4MyPkYFH1oV+2ajO44fWMvll6d64TmQMSZZmlFw2b5 H86AHFsPhOicBfQGYcn9m1tw8HVauQdWN1k7GR0yOLRZ+YP635K2PClcJ2uS0mF/ Tw0kqWo2rUYJpanznvBJbSeSe1HRVf4KNmq0G20ZI9k6TG5X7v1Rug== =igpG -----END PGP SIGNATURE-----
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