Slashdot Mirror
Encryption by Hand?
Arachn1d writes "A question for all those slashdot math-geeks out there: What's the simplest, but most secure encryption algorithm you can devise or provide a link to that can be carried out with nothing but a pen, some paper and a calculator? Bonus points for any public-key cryptography solutions!" Bruce Schneier developed an encryption algorithm designed to be performed with a deck of cards, but it's rather slow to do for fun. Well, you did say "a calculator", and if we assume a programmable calculator your options probably expand quite a bit...
No need to do all the futzing around, just pull some data from the books.
Nothing like a one-time pad that you can use over and over again... Hey, wait a second...
Even better, if you can get them: a pair of twenty sided quantum-entangled dice. That way, both sender and receiver can extend the pad at need, just by rolling up more numbers.
The only tricky part is reading the dice without looking at them. There are several ways to do this, but none of them actually work in practice and at least one of them is suspected of causing space-time errosion (& thus you will need to file an Environmental Impact Statement, including the plain text of the message being sent, thus reducing the utility of the system).
Another problem is keeping the dice cold. They have to be kept very, very cold, and of course this is very very expensive (C = A*exp(K-T)+B*N, where C is cost, K is Boltzman's constant, T is the temp., A and B are arbitrary constants related to local tax laws, and N is undefined).
But the main advantage of using quantum dice is that it would be too nerdly for words (at least three equations would be required) and you could probably get your picture in some magazine, wearing a white lab coat with coloured lights hitting you from odd angles.
-- MarkusQ
P.S. The original post was sound, but if you buy any of this post, I have a startup I'm trying to fund...
Of course, the proper way to encode the key
would be on something like Fruit Roll-Ups (TM),
which are like paper but edible. That way, both you and the recipient could eat the key after using it.
Cryptograpy has never been so delicious!!!