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> By this do you mean don't use 1024 bit keys? Would using 2048 bit (or larger) mean that the NSA wouldn't be able to buy a computer that could do the computati
by snuxoll 11y ago
> By this do you mean don't use 1024 bit keys? Would using 2048 bit (or larger) mean that the NSA wouldn't be able to buy a computer that could do the computation within a year?
Keep in mind, going from 1024 to 2048 bit DH parameters doesn't double the search space, it raises it from 2^1024 to 2^2048. At some point the search space gets so large that you'd need more energy than required to boil all of Earth's oceans to find the key, which makes such a brute-force attack implausible.
- cinquemb 11y agoI haven't had much crypto-in-practice background (outside of thought experiments), but I have some math background so I'm quite curious. Shouldn't people also be worried about non brute force attacks based on finding mathematical solutions? I mean, "The Uneasy Relationship Between Mathematics and Cryptography"[0]? [0] http://www.ams.org/notices/200708/tx070800972p.pdf http://www.ams.org/notices/200708/tx070800972p.pdf
- tptacek 11y agoThe attacks we're talking about are non-brute-force mathematical attacks (specifically, in this case, the index calculus). A pure brute-force attack on a 2^1024 search space would be comically implausible.
- netheril96 11y agoActually that is wrong. The search space of 1024 bit Diffie Hellman is about 2^80, of 3248 bit about 2^128. I failed to find a number for 2048 bit DHE.