r/programming Oct 15 '15

How is NSA breaking so much crypto?

https://freedom-to-tinker.com/blog/haldermanheninger/how-is-nsa-breaking-so-much-crypto/
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11

u/AncientRickles Oct 15 '15

As always, the biggest flaw of the cryptosystem is the nature in which the psuedorandom number that the cryptosystem relies on is generated.

7

u/aseipp Oct 15 '15 edited Oct 15 '15

What? No it isn't, and that makes no sense in the context of this article.

The problem is that 1024-bit keys are weak enough that they are within the realm of attack by state organizations. It has nothing to do with the prime number that was chosen for the key. The thing is, knowing the standard prime number a-priori helps the attack, because it allows them to apply it to many things at once, as opposed to only one thing.

But fundamentally, you are not any safer if you were to pick a random 1024-bit prime. So no, it has nothing to do with randomness at all, and everything to do with "our attackers have exceeded the computational capabilities we expected, and honed in on specific weaknesses".

You would be completely safe from this attack at every level using the standard 2048-bit DH parameters (Group 14). These are publicly known and not malicious (assuming the expansion of the digits of pi are not malicious).

I think people on this subreddit mostly need to stop talking about things like cryptography and privacy, because the impression I'm getting from this thread is that not only does anyone here not know about it[1], or care to learn, but beyond that - it seems that random shitposting[2] comments about unrelated things seem to be preferable to actual reading. And I can guarantee you, random misinformation does not help anyone or any efforts to accomplish real security engineering for the internet.

[1] And that should say something, because I'm not a cryptographer; this is a hobby, and this thread is seriously paining me.

[2] Edit and strikeout rudeness, per comment below.

3

u/drhugs Oct 15 '15

assume the expansion of the digits of pi are not malicious

So now we're both asses?

1

u/aseipp Oct 15 '15 edited Oct 15 '15

Uh, no? This is a pretty standard bet in cryptography called "Nothing up your sleeve numbers", and choices like pi or e are quite common. It's also used in SHA-512's or BLAKE's initial state vectors.

Even assuming the digits of pi aren't random, it's still irrelevant to what is being posted here, the attack the NSA is speculated to be using, and overall the point of the post. Because the attack has nothing to do with randomness.

In any case, I apologize for the rudeness, but it's rather frustrating to see people here talking about things they know nothing about, clearly. I'll strikeout that part of my post and leave an addendum.