-----BEGIN PGP SIGNED MESSAGE----- In article <199702030626.WAA14616@toad.com>, Vin McLellan <vin@shore.net> wrote:
Ian popped the 40-bit RC5 (not RC4) challenge with 259 processors, almost all standard Unix college-lab workstations, as I understand it. (RC5 has a variable block size and a variable number of rounds; but the unknown plaintexts for this contest were enciphered using a declared 12-round RC5 with a 32-bit word size.) The message Ian revealed was something like: "That's why you need a longer key!!!!!"
(The network Ian used to link his lab workstations, NOW at Berkeley, is definitely not standard, however. I think there is a description of it online; but briefly, NOW seems designed to very efficiently handle this sort of intensive distributed processing project. More important, perhaps, was the fact that Ian just chewed through the possible keys with a pure brute-force attack on the key space. His attack was not really optimized for RC5, or designed to attack any specific element in the RC5 crypto architecture.)
Actually, it was 259 _machines_, but 4 of them were 8-processor UltraSPARCs (by far the coolest machines I had access to), for a total of 287 processors. The "special" network used by the NOW cluster was irrelevant; I didn't use it at all. I used the machines on the NOW and 120 other HP workstations as regular TCP/IP clients. I started them by simply logging in to each machine, one at a time with "rsh" (well, "krsh" or "ssh" where appropriate). - Ian -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQCVAwUBMvj4REZRiTErSPb1AQFl5gP+MGlyElNu6X3IHseW6Q0EPicPa4mQs35Z koUKkAhk0qrT2CpEzw7J6dtjyTLs2BUmScEOtvU8KiBjK8aRZCsE0BHSmONWtX71 dNZu1q/+wm2oSLi1tDq0mT7bpbBR0NbO71tWgza2vTFhtP4vKvzt5SodYSN+JTYL 5DuLvpofRFs= =ly1x -----END PGP SIGNATURE-----