From the New York Times...

WASHINGTON-The Energy Department will take delivery on Wednesday of what the Government says is the world's fastest computer, capable of a peak performance of 3.88 trillion calculations, or teraflops, a second. Just to simplify things, let's assume that 1 flop == 1 decryption. I know that's not true, but it's very close, and it's certainly less than one order of magnitude off. So, with this assumption how long does it take to break various key sizes? 56 bits -- 2^56 / 3.88E12 = 5.2 hours 64 bits -- 2^64 / 3.88E12 = 55 days 80 bits -- 2^80 / 3.88E12 = 9873 years 128 bits -- 2^128 / 3.88E12 = 2.8E18 years. And now you know. Harv.