Re: manual cryptography

From: John Savard (jsavard_at_ecn.aSBLOKb.caNADA.invalid)
Date: 10/29/03 

Date: Wed, 29 Oct 2003 11:52:35 GMT

On Tue, 28 Oct 2003 17:04:36 +0100, Neko <neutral_insomniac@yahoo.com>
wrote, in part:

>What is the best paper and pencil method other than the one-time-pad of
>encrypting a message without spending more than a minute per letter
>encrypting?

I'm assuming that, since you want to avoid the one-time pad, you would
like to use a system that allows the key to be memorized.

Given that a cipher system is not considered secure unless it can
withstand an attack on the key alone, with the adversary knowing the
basic method, that runs into a problem right there, because memorizing
a key that is effectively 128 bits long is tricky.

One thing we also know is that it's easier for most people to perform
elaborate manipulations on numbers than it is on letters.

One possible idea is at

http://home.ecn.ab.ca/~jsavard/crypto/pp1324.htm

John Savard
http://home.ecn.ab.ca/~jsavard/index.html