From Major Variola (ret)
Tyler, Riad, etc:
FPGAs are used in telecom because the volumes do not support an ASIC run. Riad doesn't seem to appreciate this. He does understand that an ASIC is more efficient because its gates are used only for 1 computation, rather than most (FPGA) gates being used for reconfigurability ---useful if you can't afford an ASIC run (a million bucks a mask...) or if algorithms get tweaked (eg you release before the Spec comes out, or you are shooting for time-to-market). Clockwise an FPGA wastes time in extra wire routing although since an FPGA may be made in state of the art processes, and your ASIC may not, its a complex tradeoff. (Albeit some circuit topologies work very well on FPGAs)
So for the Cypherpunk wanting hardware (vs cluster) acceleration, FPGAs are the way to go. For TLAs, you prototype in FPGAs of course, and then make some chips in your private fab. (Same for Broadcom, etc.)
For someone making 10,000 routers, you use FPGAs.
DESCrack was solving a problem for which the x86 is not very efficient at computing --all the sub-byte bit-diddling-- and hardware is very efficient (by design in DES, after all).
Indeed, during the initial DESCrack effort, I spent some time investigating FPGAs. I came to the conclusion that it was definitely possible to build a Weiner-style pipeline machine (ie, one key tested per clock cycle), but it would be more costly than I could afford. One of the interesting twists of FPGAs is that you can optimize the circuit to the actual data being processed. For example, in DES keysearch you could hardwire into the circuit some of the subkey bits (which were determined by, say, high order key bits you rarely changed), thus simplifying the circuit. When those bits changed, you re-wrote the circuilt. Peter Trei