On Wednesday, September 27, 2017, 11:51:22 AM PDT, \0xDynamite <dreamingforward@gmail.com> wrote:


>>Hmm, as far as I'm aware, you can't do cryptanalysis on 2 characters.
>>Marxos
>> A factoid which is irrelevant in this context.
>> If you only wanted to encrypt two characters, once, you could use ROT-13 and
>> nobody would be the wiser.

>ot a factoid.  I'm making the claim that you can't decrypt it.  I
don't want to do the proof, because I can deduce it, with Pretty Good
Certainty (TM).  If you have a key approx 1/2 the size of the text,
AND you do NOT know the length of the key, you have essentially two
characters to do cryptanalysis.  Now the key may be a small enough
dictionary to do more analysis, and since you know that each set of
the same modulus is using the same key character, but without knowing
the length of the key, it's going to be next to impossible.  There are
many false leads (key-text combinations which result in what seems
like valid plaintext) and the search space becomes too large.
>Marxos

You've added the silly limiting condition that you are referring only to messages with two characters, which has virtually nothing to do with most messages sent by OTP.  

And, I observe if indeed you are only referring to two character messages, then the One Time Pad with half that number of characters, ONE character, amounts to the same thing as ROT-13, except where the number "13" is allowed to vary between 0 and 25.

Highly UNinteresting.

                    Jim Bell