Why Google is Hurrying the Web to Kill SHA-1

Post by orblivion » Tue, Sep 09, 2014, 2:30 PM UTC

spatz wrote: post #122

orblivion wrote: post #77

Understanding that this is a naive outsider perspective, I find it strange that it's any sort of emergency when a single collision has yet to be produced. And then, does the latest hash collision attack allow you to make a collision with a _specific_ target or just make a collision in general? Finally, even if you hit the target with some junk that happens to hash to the same thing, is it going to be in correct file…

When a collision is produced it will be too late. The time to act is before that happens.

Post by konklone » Tue, Sep 09, 2014, 3:07 PM UTC

brongondwana wrote: post #101

"SHA1 and other hash algorithms generate a digital fingerprint that in theory is unique for each different file or text input they sign." ... and there it goes, any credibility I would give the author. There's dumbing down the content for a non-technical audience, and there's not understanding.

Post by venaoy » Tue, Sep 09, 2014, 6:36 PM UTC

illumen wrote: post #120

cgjaro wrote: post #99

Earlier quoted context omitted.

I don't know if "10 years" falls in your definition of "next few years". For a viable rogue CA attack, you need a chosen-prefix attack. Current best research ( https://marc-stevens.nl/research/papers/EC13-S.pdf ) shows it should take 2^77.1 SHA-1 compression calls to do a chosen-prefix attack. Say this is improved to 2^65 within the next 10 years. Right now a good GPU (AMD R9 290) can do 3 billion SHA-1 compression c…

Firstly, GPUs haven't followed More. Secondly, multiple sha1 ASIC exists. Thirdly, WebGL has made it trivial to gain vast GPU resources. 20,000 viewers for two hours can be bought for $20. Fourthly, I don't care.