6 ms·
"RSA-210" is the official name for this challenge, but it is a bit of a misnomer. The modulus has 210 decimal digits but about 210 * log2(10) = 697 bits. EDIT:
by simonster 13y ago
"RSA-210" is the official name for this challenge, but it is a bit of a misnomer. The modulus has 210 decimal digits but about 210 * log2(10) = 697 bits.
EDIT: Wikipedia article says 696 bits.
- trebor 13y agoAh, thank you. I hadn't heard of the challenge and didn't know the size of the number being factored. So this will mainly affect 1024 bit keys, rather than 2048+ bit keys, I presume.
- jd007 13y agoIt doesn't really even affect 1024 bit keys as even the largest RSA keys factored (this one is close but isn't) are quite a bit far away from 1024 (remember factoring difficulty scales exponentially with number of bits, not linearly). But 2048 bit keys are recommended I believe.
- kingkilr 13y agoFor new keys, 4096 is preferred.
- tptacek 13y agoI don't think it's that simple. A 4096 bit key is extremely unlikely to get you fewer bits of security than a 2048 bit key. But the thing that makes 2048 bit keys a realistic threat is likely to make the "preference" be for something other than RSA entirely.
- sdevlin 13y agoIf 2048-bit RSA is vulnerable, then RSA is probably toast.
- makomk 13y agoI know some of the CAs are using 4096-bit keys for their long term signing keys, but those are going to be in use for over a decade and are a major target. Everyone else seems to use 2048-bit.
- trebor 13y agoI know that being able to factor ~670/1024-bits isn't that impressive (overall). But the fact that it is possible to develop the software this far shows that it's mainly a hardware problem. Enough parallelization into GPU cores with a significant system, and I think that cracking a 1024-bit key comes to less than a week.