ARS Technica reports that 1024-bit RSA encryption may soon not be safe enough anymore. Encryption researchers recently managed to break down a 307-digit composite Mersenne number into primes, and RSA keys are the next target.
"Last time, it took nine years for us to generalize from a special to a nonspecial, hard-to-factor number," Lenstra said in a statement, referring to a 155-digit number that his team had broken previously. More recently, a 200-digit non-special number was factored in 18 months and roughly 50 years of computer time. This 307-digit crack took even less (human) time, which Lenstra credits to more powerful computers and improved code. "I will not make predictions [about the future of 1024-bit encryption], but let us just say that it might be a good idea to stay tuned."
Why does anyone care? While your average Joe or Jane on the street will not be able to crack a 1024-bit RSA key anytime soon, experienced attackers might not have such a hard time. Getting the computing power to crack a 1024-bit key could be as easy as employing a decent-sized botnet or two.