Re: Strongest encryption algorithm

Woody Brison wrote:
fermineutron wrote:
Joseph Ashwood wrote:

6) no character in plaintext should encode to itsef in cyphertext.
Again, very bad idea. Let's extend this to where you should actually be
thinking: no bit in the plaintext should encode to the same bit in the
ciphertex. This is trivially breakable as there is not introduction of the
key. The same applies when you work on the character, or even file level,
although to a lesser degree.
Interesting extrapolation, but it only applies on a bit sized alphabet,
initially i was thinking of a byte sized alphabet.

In Codebreakers, Kahn details an incident in WW2 where
a German code, enigma as I remember, was given to the
Italians for their use. Some Italian wanted to send
a test message and just leaned on the L key. The
resulting cyphertext had zero L's in it. The attacker
noticed this and after some thought realized that "no
character in plaintext ... encode[d] to itsef in
cyphertext." And proceeded to break open the whole system.

Enigma had been broken before then, before the war, in fact, by the Polish.

--Mike Amling
.

Relevant Pages

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