From: Dave Burt <dave@...>
Date: 2005-01-09T15:31:24+09:00
Subject: Re: [SUMMARY] Cryptograms (#13)

> Solving a cryptogram by brute force is prohibitively expensive.  The 
> maximum
> number of possible solutions is 26!, or roughly 4*10^26, so the first 
> challenge
> is to pare down the search to something manageable.
>
> Both my solution and Michael's begin with the insight that any word, 
> either a
> regular dictionary word or a cryptographic token, can be viewed as a 
> pattern of
> repeated and non-repeated characters.  For example, "banana" has the 
> pattern [1
> 2 3 2 3 2], where the first letter is used exactly once and the second 
> letter
> is used three times and the third letter is used twice.  These patterns 
> group
> all known words into families.  The word, banana, belongs to the same 
> family as
> the word, rococo.

I'm sorry I didn't have time to give this a go.

You looked at matching words. I'm wondering if you could get as good a go 
with reasonable-sized ciphertexts using a letter frequencies method? (i.e. 
the most common letters in an English text are E, then T, etc.) Perhaps you 
could apply letter frequencies first before moving on to match common words, 
even.

Cheers,
Dave