Re: VMs: No stats no fun ---> no stats no blinkers! :-)

[Nick Pelling <incoming@xxxxxxxxxxxxxxxxx>]

Hi Rene,

> > Consider the following (badly designed) pair
> > cipher:-
>
> Well, this is a very bad example, or indeed an
> excellent one, depending on the way you look at
> it :)

:-)

Note that Vigenere's Alphabeth Northmanique is perhaps an even worse 
example than mine. :-)

http://www.chass.utoronto.ca/~wulfric/rentexte/vigenere/chif_f338r1.jpg

Of course, any moderately experienced cipher-maker would try to prevent 
such a verbose cipher's being so visually obvious. The key statistical 
indicators for verbose ciphers are (a) the small number of symbols in their 
(apparent) cipherbet - for example, my cipher used only 11, and Vigenere's 
12 - and (b) their low apparent predictive entropy. While careful design 
can reduce the visibility of these artefacts, perhaps it cannot remove them 
entirely... :-)

Cheers, .....Nick Pelling...... 


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