Re: Relevant information

Op dinsdag 30 september 2003 19:17, schreef u:
> Hans Steegers wrote:
> >[11] Note that SHA comes from the National S{neek|noop|pook|ecurity}
> > Agency. The NSA fooled the public once: DES coded messages could easily
> > be decoded by the NSA for 20 (!!!) years before the (so called expert)
> > cryptographers discovered differential crypto-analysis and found this
> > weakness.
>
> Rewriting history Hans?  What was surprising in the discovery of
> differential crypt-analysis wasn't how weak DES was, but how strong the
> addition of S-Boxes made it to this new form of attack.  Biham and
> Shamir's work probably exposes the limits of what the NSA knew in the
> '70s, but trying to describe NSA's attempt to strengthen DES against
> differential cryptanalysis as a fatal weakness inserted by NSA is just
> bizarre.   DES remains significantly stronger than it would have been
> without the addition of S-Boxes to IBM's original proposal, and Biham
> and Shamir's paper proves that the arrangement of the S-Boxes is
> significantly better than a random placement would have afforded.  At a
> difficulty of 2**37, the S-Boxes are sub-optimal, but with a typical
> random arrangement strength of 2**18 to 2**20, it is clear that DES was
> strengthened, not weakened by the involvement of the NSA.

It is a correctly translated and compacted summary (except for NSA abbrev) of 
an alinea in a dutch artlcle I found when looking for information on SHA. 
I couldn't resist to include it. Where did you read "...fatal weakness 
inserted by NSA..."?  Furher discussion is IMHO off-topic for this list.
Thank you for your additions and have a nice day!



-- 
_____________________________________________

Hans Steegers



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