From: Germano Caronni <caronni@tik.ee.ethz.ch> Date: Mon, 10 Feb 1997 18:52:23 +0100 (MET) To: crypto-challenge@rsa.com Cc: gec@acm.org, challenge@tik.ee.ethz.ch, coderpunks@toad.com Subject: RC5-12/32/6 contest solved

challenge: RC5-32/12/6 solution: 74 a3 53 cc 0b 19 name: Germano Caronni et al. address: Germano Caronni Talstrasee 7 CH-8102 Oberengstringen (Switzerland) email: gec@acm.org phone: +41 1 6327006 time: from start of contest until Mon Feb 10 18:52:23 1997 method: again, massive distributed coordinated keysearch done:

Congratulations! This is the longest symmetric key ever brute forced in public. Now, onto cracking DES, which is probably easier than 56 bit RC5. I have NT/Win95/(portable C) code and executables available to US/Canadian citizens in the US/Canada. If you want a copy (I'm up to version 0.6, a late beta), then send ptrei@acm.org your: 1. Real name and residence address. 2. A statement that you are aware of and will abide by the US/Canadian export regulations. 3. A statement that you are a US/Canadian citizen, or a US Green Card holder. 4. The email address to which to send the software. I will hold this information in confidence. Peter Trei trei@process.com