Let's have some fun by developing a very simple algorithm that utilizes diffusion and substitution. It won't be all that strong, but we can understand it easily. Let's call it the "Gnosis cipher," after the name of my company (most anyone with a real interest in breaking it will be able to "know" all the plain text encrypted with it). For pedagogical convenience, the Gnosis cipher will operate on characters rather than on bits. This cipher should not be difficult to encode and decode with pencil and paper. An honorable mention will be given to the tutorial taker who e-mails me the most clear, interesting, or clever "crack" of the Gnosis cipher.