Re: CRYPTO: Small cryptosystems

Eliezer Yudkowsky (sentience@pobox.com)
Mon, 30 Dec 1996 17:11:32 -0600


> 2) In an algorithm that is large, complex and messy, it's very easy to make a
> blunder. When you add yet another wheel within a wheel you may think you're
> making it more secure, but you may be doing the opposite, it's hard to
> know how the change will react with all the other parts of a very messy
> algorithm. You may have actually have created a small hole in the system
> through which an attacker can extract a little piece of information,
> information he shouldn't have, information he can use to expand the hole
> until he can drive a truck through it.

In the German "Enigma", they added a little "improvement" which made it
impossible for any letter to be encoded as itself. That, essentially,
is how the Allies cracked it.

-- 
         sentience@pobox.com      Eliezer S. Yudkowsky
          http://tezcat.com/~eliezer/singularity.html
           http://tezcat.com/~eliezer/algernon.html
Disclaimer:  Unless otherwise specified, I'm not telling you
everything I think I know.