Dear Jake, > Very true, but note that exhaustive searching of small key spaces (say > <2^64 keys) is becoming possible on dedicated hardware. Someone (can't > remember who) proposed a machine for searching the DES keyspace in a few > _days_, which you could build for about $1M. For what it's worth, $1B would > buy you a machine to do it in a few hours. > Anyway, I think we're getting a little bit tangental now... > Regards, > Jake. That was Michael J. Wiener of Bell Northern Research in 1993. The paper is 'Efficient DES Key Search'. His proposed machine would have cost about $1M and would have found a key in about 3.5 hours. Shalom, JBB.