\nMost modern cryptography relies on single large numbers that are the product of two primes. If you know the numbers, it’s relatively easy to encrypt and decrypt data; if you don’t, finding the numbers by brute force is a big computational challenge. But this challenge gets easier every year as processor speed and efficiency increase, making “secure” a bit of a moving target. The paper describes how the process was done with commodity hardware, albeit lots of it. <\/p>\n
\nTheir first step involved sieving, or identifying pairs of prime integers; that took the equivalent of 1,500 years on one core of a 2.2GHz Opteron; the results occupied about 5TB. Those were then uniqued and processed into a matrix; because of all the previous work, actually using the matrix to factor the RSA value only took a cluster less than half a day. Although most people aren’t going to have access to these sorts of clusters, they represent a trivial amount of computing power for many organizations. As a result, the authors conclude, “The overall effort is sufficiently low that even for short-term protection of data of little value, 768-bit RSA moduli can no longer be recommended.” 1024-bit values should be good for a few years still.\n<\/p>\n
\nGiven that these developments are somewhat inevitable, even the authors sound a bit bored by their report. “There is nothing new to be reported for the square root step, except for the resulting factorization of RSA-768″ they write. “Nevertheless, and for the record, we present some of the details.” Still, they manage to have a little fun, in one place referencing a YouTube clip of a Tarantino film following their use of the term “bingo.”\n<\/p>\n