Re: Enigma machine strenght using a computer

On Sun, 31 Dec 2006 12:04:57 -0800, Paul Rubin wrote:

"Jean-François Michaud" <cometaj@xxxxxxxxxxx> writes:
No, the algorithm doesn't share the same weakness. The idea is closer
to a one time pad. The output of the enigma machine is XORed to the
content of the plaintext. It's not necessarily likely that a letter
will be encoded to itself but its possible. A rotor machine feeds
another rotor machine and the output of the second machine is XORed to
plain text.

How do you decrypt? The original Enigma was self-inverting, but the
thing you describe is not.

He's not using rotors to transform characters, he's using rotors to create
a key stream that's XORed to the plaintext.

XOR is inherently self-inverting.

In effect, what he's doing is closer to Vernam two-tape than to Enigma,
only with a bunch of short tapes instead of one large one.

--
Nearly every electrical engineer believes deep in his heart that he
is better at writing computer software than any computer programmer,
and can show as proof the fact that he has written a number of small
applications, each of which was done quickly, easily, and exactly met
his needs.

.