how fast is fast des these days? (i have measured over 2 mbps on decent workstations.) i was in a meeting today attended by someone from nsa who said that 2.4 gbps des chips exists today. (he got real silent after blurting this out. hmm.) 2.4 gbps is 37.5 million des per sec. it is probably not much challenge to put together a 65,536 element machine, which would run at 2.5 trillion des per sec. if i have my arithmetic right, this could exhaustively test the space of 56 bit keys in about eight hours. I don't know of any 2.4 gbps DES chips, but DEC has built a 1 gbps chip. They've even published a technical report on it, though I don't have the number handy. But there's more to know than simply the raw speed. First of all, most real DES chips -- i.e., those designed for encryption, rather than brute-force cryptanalysis -- are optimized for encrypting large blocks of data. Key-loading is a different operation, and that might not go nearly as fast. Any hardware assists (i.e., DMA) would be for the data, not for the next key to use on the same block of data. Second, what does this chip cost? If it costs, say, 10x what the DEC chip costs, it's not cost-effective; you can build your DES-cracker more cheaply with the slower chips. (The DEC TR gave cost figures for DES-cracking...)