Re: [openpgp] Fingerprints and their collisions resistance

[Andrey Jivsov <[e-mail]>]

On 01/04/2013 02:53 AM, Christian Aistleitner wrote:
> Hi Andrey,
>
> On Thu, Jan 03, 2013 at 03:30:14PM -0800, Andrey Jivsov wrote:
>> Instead of 80 bit is security (birthday
>> bounds) SHA-1 is listed as 51 bits on
>> http://en.wikipedia.org/wiki/Message_digest.
>
> Since you mention the 51 bits part again and again ...
>
> Do you have any data / research underpinning this 51 (Besides
> Wikipedia)?
>
> After all, the cited Wikipedia page links to the retracted variant of
> an article :-(
>
> Otherwise, the best /theoretical/ result that I know of is just
> above 60.

It looks like this is from the paper "Classification and Generation of 
Disturbance Vectors for Collision Attacks against SHA-1"
published in 2011 in Designs, Codes and Cryptography
http://link.springer.com/article/10.1007%2Fs10623-010-9458-9?LI=true
with 27 citations in Google scholar. There you can find a dozen of 
different copies (or minor revisions?) of the paper and Wikipedia links 
one of them.

Should we rather say that the _practical_ value is about 60 (it's not to 
say that 2^60 is that practical, but that there is an expensive but an 
actionable attack plan). The following post leads the reader to the 
algorithm : 
http://www.schneier.com/blog/archives/2012/10/when_will_we_se.html