Comment by adastra22
2 hours ago
RSA-1024 is approx 6 bits more security than the RSA-260 challenge, so ~64x more work to factor. That is negligible by cryptographic standards.
We don't know yet how much work OP put into factoring the RSA-260 challenge. No doubt it was a lot, but probably done with general purpose GPU hardware. That will continue to get cheaper to mount in the near future, and we ought to assume that nation states have access to RSA factoring hardware that would be multiple orders of magnitude more efficient.
It is quite likely that there are at least two actors (US and China) that can break RSA-1024, and they are no doubt working through a priority list of all accessible servers with such weak keys. If your firewall is not broken & now back-doored, it is only because you're not important enough to have gotten to yet.
RSA-2048 (or better, RSA-3072) is usually a drop-in replacement. ECC would be even better. There is no reason not to.
You are right that there are better options and there is no excuse not to choose something better today. But that’s not what GP is arguing! It’s just that: For any given interest level there is no way that expending the resources to attack the RSA key is valuable! You are either willing to expend resources then attacking the owner is far cheaper or not then you are also not investing weeks-to-month of cluster time.
And from that perspective RSA-1024 is still perfectly adequate