Comment by pseudohadamard

There's also the question of why anyone would bother. You can factor RSA-1024 today in about a year with a national-lab-level supercomputer. Which 1k-bit RSA key would you shut down a national lab for a year for to factor? Heck, which key would you shut it down for a week for to factor? There's no single key out there of any interest when you can just spear-phish your intended target, or get RCE on their unpatched router, or get the cleaners to plug in a USB key and let it do its thing while they're vaccuuming, or whatever.