21 May 1999. Thanks to MS.

Date: Fri, 21 May 1999 10:36:39 -0600 From: Mike Stay <staym@accessdata.com> To: coderpunks@toad.com Cc: cryptography@c2.net Subject: quantum codebreaker There is a paper just published today on the Los Alamos Nat'l Labs preprint site: http://xxx.lanl.gov/abs/quant-ph/9905064 on how to simulate arbitrary nonlinear quantum dynamics. They give examples of existing systems where the effect has already been seen and then give a general description of using feedback to make a quantum system behave nonlinearly. They show that in such systems, distances between quantum states are NOT preserved. It was previously published hat if QM was nonlinear at all, one could do a quantum search in log N time instead of sqrt N time. http://xxx.lanl.gov/abs/quant-ph/9801041 http://xxx.lanl.gov/abs/quant-ph/9804025 If today's paper is correct, then it's just a matter of sufficient technology to break ANY code with a known-plaintext attack. -- Mike Stay Cryptographer / Programmer AccessData Corp. mailto:staym@accessdata.com