The use of idle cycles on workstations or PCs for brute force attacks made me think about the economics of this problem. How cheaply could a massively parallel system be built for key cracking? Much of the cost and complexity of current massively parallel systems is in the inter-processor communications and memory systems. Why not build a system with a large number of single chip processors (ROM/RAM/IO on one chip) and a simple/slow/cheap communication bus? I'm assuming that each processor can attack a small chunk of the keyspace without needing any external support. One or more PC boards could be populated with an array of cheap processors. There would be a master controller to assign chunks of key space and check for results. It could also download the software if it was to be stored in on-chip RAM. A PC board could be designed that would provide 5V power, a shared serial I/O bus and a wired-or interrupt for the microprocessors to signal the master controller that a key has been cracked. What would be a good microprocessor for this task? It would have to be cheap, reasonably low power with lots of integer MIPS. A decent amount of on-chip RAM would allow the software to be downloaded instead of being masked or burned into ROM. 1000 processors could be put into a relatively small box, lets say 10 boards each containing 100 single chip microprocessors. It shouldn't cost more than $10-$20 per processor, about the same total cost as one decent workstation ($10K-$20K). -- John A. Limpert johnl@Radix.Net