[Cryptography] Collisions w/SHA-1 ~$100,000 TODAY

[ianG]

On 8/10/2015 15:37 pm, Henry Baker wrote:
> FYI -- 64-GPU cluster produces cheap SHA-1 collisions.
>
> “We just successfully broke the full inner layer of SHA-1.
>
> We now think that the state-of-the-art attack on full SHA-1 as described in 2013 may cost around 100,000
> dollar renting graphics cards in the cloud.”
>
> "However, we showed that graphics cards are much faster for these attacks and we now estimate that a full SHA-1 collision will cost between 75,000 and 120,000 dollar renting Amazon EC2 cloud over a few months today, in early autumn 2015."
>
> "This implies that *collisions are already within the resources of criminal syndicates*, almost two years earlier than previously expected, and one year before SHA-1 will be marked as unsafe in modern Internet browsers."
>
> https://sites.google.com/site/itstheshappening/shappening_article.pdf
>
> https://sites.google.com/site/itstheshappening/shappening_PR.pdf
>
> https://sites.google.com/site/itstheshappening/
>
> The Shappening: freestart collisions for SHA-1


Can anyone provide a pointy-eared boss description of what a *freestart* 
collision is?

iang