Hiding code from intruders, a different slant on an old question

[Ian Kelly]

On Wed, Oct 7, 2015 at 6:01 PM, Dennis Lee Bieber <wlfraed at ix.netcom.com> wrote:
> On Wed, 7 Oct 2015 13:05:07 +0000 (UTC), alister
> <alister.nospam.ware at ntlworld.com> declaimed the following:
>
>
>>With a simple Cesar the method is "shift the alphabet by 'X' characters
>>and X is the key
>>
>>if the key is unknown then the attacker still has to brute force the
>>method (admittedly with only 25 options this is not difficult)
>
>         But who'd consider that with just one-case and alphabet only...
>
>         At the least include upper, lower, numbers, and basic punctuation --
> that will add a few more cycles of computation time to break <G>

It doesn't really matter how much you add; any Caesar cipher is going
to fall easily to just a little bit of frequency analysis. Consider an
extreme case, where the range of X is the size of the entire Unicode
character set. If the message is written in a Latin-based character
set, chances are good that the majority of the characters will fall
within a range of <96, giving the attacker a great starting point to
brute-force from.