5 ms·
As you probably know, the computing time in the worst case scenario for brute forcing a cryptographic key generally doubles by each bit added. That is, it would
by rbtms 9d ago
As you probably know, the computing time in the worst case scenario for brute forcing a cryptographic key generally doubles by each bit added. That is, it would take twice the effort to brute-force 129 bits compared 128 bits.
The security of RSA however depends on the factoring of very large numbers, and that means that for example, RSA-2048 doesn't translate into 2048 bits of security but 112 (roughly symmetric equivalent) bits based on the best factoring algorithms (for comparison, the RSA-512 the article mentions has an 56 bit equivalent and RSA-1024 has a 80 bit equivalent security, so RSA-1024 would take roughly 2^(80-56) ~= 17 million times to compute the worst-case scenario and RSA-2048 would take 2^(112-80) = 4.3 thousand million times more).
According to the Wikipedia article on RSA numbers, RSA-220 (66b) was factored in 2016, RSA-230 (69b) in 2018, RSA-240 (72b) in 2019 and RSA-260 (76b) this year, which is too close to RSA-1024 (80b) to be comfortable.
For RSA-250, the team reported it took "roughly 2,700 core-years, using Intel Xeon Gold 6130 CPUs at 2.1 GHz.". I am not going to (or feel qualified to) make estimates of how that would translate to RSA-1024, but it does sound plausible given enough resources.
- rurban 8d agoRSA-1024 about 2000 GPU years. With clusters of size 100k typical right now. https://x.com/sweis/status/2095570657367278051 https://x.com/sweis/status/2095570657367278051 Consider it broken already for AI or NSA guys