binary file compare...
rhamph at gmail.com
Wed Apr 15 21:05:39 CEST 2009
On Apr 15, 12:56 pm, Nigel Rantor <wig... at wiggly.org> wrote:
> Adam Olsen wrote:
> > The chance of *accidentally* producing a collision, although
> > technically possible, is so extraordinarily rare that it's completely
> > overshadowed by the risk of a hardware or software failure producing
> > an incorrect result.
> Not when you're using them to compare lots of files.
> Trust me. Been there, done that, got the t-shirt.
> Using hash functions to tell whether or not files are identical is an
> error waiting to happen.
> But please, do so if it makes you feel happy, you'll just eventually get
> an incorrect result and not know it.
Please tell us what hash you used and provide the two files that
If your hash is 256 bits, then you need around 2**128 files to produce
a collision. This is known as a Birthday Attack. I seriously doubt
you had that many files, which suggests something else went wrong.
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