[Haskell-cafe] module Crypt_Discordian - code critique requested

[David Roundy]

On Wed, Feb 23, 2005 at 12:27:19AM +0000, Terrence Brannon wrote:
> But anyway, here is the algorithm in case you don't enjoy tilting your 
> head to read a page:
> 
> Step 1. Write out message (HAIL ERIS) and put all vowels at the end
> (HLRSAIEI) 
> 
> Step 2. Reverse order (IEIASRLH)
> 
> Step 3. Convert to numbers (9-5-9-1-19-18-12-8)
> 
> Step 4. Put into numerical order (1-5-8-9-9-12-18-19)
> 
> Step 5. Convert back to letter (AEHIILRS)
> 
> This cryptographic cypher code is GUARANTEED TO BE 100% UNBREAKABLE
> 
> .. so says the Principia Discordia. But I think we can generate and
> test to break it.

Isn't it guaranteed unbreakable simply because there's no way to decrypt
it? Since there isn't a one-to-one mapping of cyphertext to plaintext, I
don't think it's actually a form of encryption.  Basically it's the same as
the sort function, which is also not invertible.
-- 
David Roundy
http://www.darcs.net