Re: [ANN] MD5 1.0.2 Released (OT)

["Aaron Brown" <arundelo@...>]

Steve Heller wrote:

> On Thu, 10 May 2007 02:02:04 -0400, Dave Dodge
> <dododge@dododge.net> wrote:

> > This design requires that every unique block of data, in
> > every file in the filesystem, has a unique hash value.  A
> > collision results in data loss.
> >
> >    "Using the Sha1 hash function, the probability of a
> >    collision is less than 10^-20. Such a scenario seems
> >    sufficiently unlikely that we ignore it [...]"
> >
> > http://plan9.bell-labs.com/sys/doc/venti.html
>
> For how big a filesystem? If you have enough blocks, the
> probability of a collision will be 1.

Follow the link; the number quoted is for

> [A] system that contains an exabyte (10^18 bytes) [a
> million terabytes] stored as 8 Kbyte blocks (~10^14
> blocks).

--
Aaron
http://arundelo.com/