From: root@mauve.demon.co.uk
Message-Id: <200308281810.TAA24356@mauve.demon.co.uk>
Subject: Re: Lockless file reading
To: jamie@shareable.org (Jamie Lokier)
Date: Thu, 28 Aug 2003 19:10:05 +0100 (BST)
Cc: root@mauve.demon.co.uk, ragnar@linalco.com (Ragnar Hojland Espinosa),
       davids@webmaster.com (David Schwartz), tss@iki.fi (Timo Sirainen),
       linux-kernel@vger.kernel.org
In-Reply-To: <20030828173522.GA8581@mail.jlokier.co.uk> from "Jamie Lokier" at Aug 28, 2003 06:35:22 PM
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> 
> root@mauve.demon.co.uk wrote:
> > > Probability on the order of 2^-32 with MD5 any-pairs collision.
> > MD5 is 128 bit output, so that's around 2^64 pairs before you have a birthday.
> 
> Right.  Dozy me :)
> 
> > > Do you still have the GIFs?
> > 
> > There arn't that many GIFs in the world.
> > I'd be really surprised if there were that many pictures in the world.
> 
> I'd be really surprised if what you saw wasn't a software error,
> misreporting or miscalculating the MD5.

Or perhaps more likely, truncating the hash to 32 bits, in which case for most
people there won't be a problem, as a collision isn't likely until you get
to tens of thousands of images.

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