Wei Dai writes:

factor RSA keys of bit 512: 20 minutes 768: 50 days 1024: 100 years 2048: 1e11 years

If you are reading this from an archive, divide the brute force numbers by 4**(your current year-1995), and the factoring numbers by 8**(your current year-1995), for a factor of 2 improvement per year in each of the following: average CPU power, number of computers on the Internet, and factoring algorithm.

BUT, one must remember that the power of 2 increase is going on during the 100 years effort to break the 1024 bit case, so, by these assumptions, the 1024 bit key will break sometime in the 6th year! Fred G. Jon Goldberg