Re: crypto for Joseph Ashwood, cryptologist or blowhard?

Joseph Ashwood wrote:
> "Grumble" <devnull@kma.eu.org> wrote in message
> news:d8m1o8$sr0$1@news-rocq.inria.fr...
> > Prof. Jonez wrote:
> >
> > > How much of a moron must you be to not know the difference between
> > > 3DES and 3DEA?
> >
> > I would, most definitely, love to be told the difference between
> > 3DES and 3DEA. Pray tell.
>
> In this case (it's not a standard cipher) it refers to triple-IDEA in
> EDE mode. This is based on the 3DES link on the website, which while
> informative enough for this purpose is generally pointless without a
> reference to the design of IDEA (which is patented and that would
> probably be another way of getting rid of this company).
>
> The other proposed theory is the one that would actually make sense,
> meet the designation used in cryptography, and be accurate. This
> stems from the fact that the Digital Encryption Algorithm (DEA for
> short) forms the basis of the Digital Encryption Standard (DES) which
> would make 3DEA the same as 3DES.

From: "Joseph Ashwood" <ashwood@msn.com>
Newsgroups: sci.crypt
Subject: Re: Cascading different algorithms?

Message-ID: <wXUbe.2094$zu.569@newssvr13.news.prodigy.com>
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Date: Wed, 27 Apr 2005 23:08:12 GMT

Actually 3DES was used because it was the most analyzed around, this came as
a result of DES. If the key size were the only consideration we would have
all switch to IDEA or Blowfish or any of the dozens of other good solutions.
The tripling of the rounds that is the result of the process actually serves
a very solid purpose, and the change of keys deals with the rest, leaving
only those attacks that work on the structure of the new cipher (e.g. the
attacks on 3DES work this way). 3DES was created because someone said why
not, 3DES remained because it resisted everything anyone threw at it for
over 2 decades, this was in large part because of the fundamental structure
of the triple encipherment. The only situation where multiple encipherment
with the same cipher would not increase security is in the unlikely case
that it forms a group, IIRC there is actually a proof that Rijndael does not
(Rijndael was named AES but much of the original theory is easier to find
regarding Rijndael). The 7 layer encipherment is the next reasonable step in
the process.
                    Joe
Received on Thu Sep 29 21:44:28 2005