🚀 go-pugleaf

Ari.Huttunen@hut.fi (Ari Juhani Huttunen) writes:
: In article <1992Sep7.202207.12500@fwi.uva.nl> lankeste@fwi.uva.nl (Branko Lankester) writes:
: 
: ! The new faster
: ! conventional cipher, called IDEA (International Data Encryption
: ! Algorithm), was developed at ETH in Zurich by James L. Massey and
: ! Xuejia Lai.  Preliminary evidence suggests that IDEA may be more
: ! resistant than the DES to Biham & Shamir's highly successful
: ! differential cryptanalysis attack.  Biham and Shamir have tried 
: ! unsuccessfully to find any weaknesses in the IDEA cipher.
: 
: Has the IDEA cipher a longer key than DES and is it thus more resistant
: to trying out all possible keys? Does the IDEA cipher use transpositions
: interleaved with substitutions or some other algorithm? Is a paper 
: describing IDEA generally available? (I'm not interested enough to order
: a copy by mail from Switzerland.)

Yes, IDEA has a 128 bit key.  It's rather beautiful algorithm,
involving multiplications mod 65537 (which is prime, so the
multiplications are invertible because every number (except zero) has
an inverse mod a prime), additions mod 65536, and XORs.  These
operations are combined in a network which thoroughly scrambles the
data.  There are no table lookups or bit permutations at all.

It's described in the proceedings of EUROCRYPT '91 (at least I think
it was that one, but I haven't got a copy here).

BAD NEWS: It's PATENTED.  Not just in the USA but in Europe as well.
If enforced, this patent will probably prevent the widespread adoption
of this algorithm.  A great shame.

: --
: ...............................................................................
: Ari Huttunen   			       Any similarity to other alien life forms
: 				          is purely coincidental.
: 					      <Alien 3 misquote>

Andrew.