[darcs-users] Re: File name too long

[John Meacham]

On Wed, Oct 15, 2003 at 12:42:43PM +0200, Peter Simons wrote:
>  > Can anyone explain why collisions should be a concern ?
> 
> Chances are pretty good that 99% of the users will never have a
> collision. But if someone does -- and Murphy teaches us that someone
> _will_, eventually -- the software should be able to deal with it one
> way or another, IMHO.

collisions are not a concern. think about how big a space of 160 bits
is. it is not that 99% of the users will never have a collision, it is
that there will never be a collision. if every single person in the
world created a patch every second for the next thousand years, the
chances of collision are roughly 1 in 1.2e+30 (thats 30 zeros) (okay, my
math is fuzzy. but you get the idea)

A whole lot of much more important algorithms (think encrypted bank
transfers and database systems) assume that SHA1 hashs cannot collide as
a basic principle. 

the point being, don't worry about collisions. it is a nonissue. it
won't happen. in fact if you can come up with two patches with the same
SHA1 hash I will buy you a beer. it is much more likely your repository
will be hit by a meteor.
        John
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John Meacham - California Institute of Technology, Alum. - john at foo.net
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