From: "Perry E. Metzger" <perry@piermont.com>
Date: Tue, 27 Aug 1996 14:12:39 +0800
To: "JOHN E. HOLT" <76473.1732@compuserve.com>
Subject: Re: The POUCH
In-Reply-To: <960826234448_76473.1732_BHT119-3@CompuServe.COM>
Message-ID: <199608270104.VAA27340@jekyll.piermont.com>
MIME-Version: 1.0
Content-Type: text/plain



"JOHN E. HOLT" writes:
> The Pouch uses a 64 x 64 block product cipher, a 1024 bit random
> initialization vector and the CBC technique.  Most experts agree
> that such an implementation is highly resistant to all forms of
> cryptographic attack.

Thats just plain wrong.

Some block ciphers are highly resistant. Some block ciphers crack open
like eggs. Being a "block product cipher" doesn't in any way make you
"highly resistant to all forms of cryptographic attack".

> An unpublished algorithm forces them into reverse engineering the computer
> programs to learn the algorithm.

The principle in the modern world of crypto is that your cipher must
be resistant to attack even if the attacker knows all details of it.

Furthermore, the principle in buying crypto is to know that 99% of
crypto on the market is junk, and that if you can't find out how it
works its probably not any good at all.

Perry