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Re: I don't think that collides the way you think it does

2009-05-05 17:48:05

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On May 5, 2009, at 12:18 PM, Daniel Franke wrote:

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Jon Callas <jon(_at_)callas(_dot_)org> writes:

Adi Shamir has pointed out for years now that no one has found *any*
first or second preimage collision for SHA1. I'll shill for him here.

The new results for 2^52 work, assuming it's actually doable, are
still for migrating a bitstring into two dependent bitstrings that
collide. This has significance for people who run CAs with sequential
serial numbers, or who want to tweak PDFs to project the future, or
create binary distributions that have and do not have malware. It's
serious *for* *those* *and* *similar* *cases*.

I think you mean "no one has found any first or second preimage
*attacks* for SHA-1".  To the best of my knowledge, nobody has found  
any
SHA-1 collisions at all, either chosen or otherwise.  The 2^52  
result is
still theoretical, because while 2^52 hash operations is tractable  
for a
WFO, it's still a formidable amount of work, and Cameron McDonald is  
not
a WFO.

Thank you for the further clarification. You are correct.

        Jon


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