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Re: MD5 in the read path


Collisions don't matter in the partitioner.

On Wed, Sep 26, 2018, 6:53 PM Anirudh Kubatoor <anirudh.kubatoor@xxxxxxxxx>
wrote:

> Isn't MD5 broken from a security standpoint? From wikipedia
> *"One basic requirement of any cryptographic hash function is that it
> should be computationally infeasible
> <
> https://en.wikipedia.org/wiki/Computational_complexity_theory#Intractability
> >
> to
> find two non-identical messages which hash to the same value. MD5 fails
> this requirement catastrophically; such collisions
> <https://en.wikipedia.org/wiki/Collision_resistance> can be found in
> seconds on an ordinary home computer"*
>
> Regards,
> Anirudh
>
> On Wed, Sep 26, 2018 at 7:14 PM Jeff Jirsa <jjirsa@xxxxxxxxx> wrote:
>
> > In some installations, it's used for hashing the partition key to find
> the
> > host ( RandomPartitioner )
> > It's used for prepared statement IDs
> > It's used for hashing the data for reads to know if the data matches on
> all
> > different replicas.
> >
> > We don't use CRC because conflicts would be really bad. There's probably
> > something in the middle that's slightly faster than md5 without the
> > drawbacks of crc32
> >
> >
> > On Wed, Sep 26, 2018 at 3:47 PM Tyagi, Preetika <
> preetika.tyagi@xxxxxxxxx>
> > wrote:
> >
> > > Hi all,
> > >
> > > I have a question about MD5 being used in the read path in Cassandra.
> > > I wanted to understand what exactly it is being used for and why not
> > > something like CRC is used which is less complex in comparison to MD5.
> > >
> > > Thanks,
> > > Preetika
> > >
> > >
> >
>