On Wednesday, September 27, 2017, 7:24:22 AM PDT, \0xDynamite
   <dreamingforward@gmail.com> wrote:
   >>>Well if they don't know the key length, then using somewhere between
   >>> 1/3 and 2/3 should make it unbreakable.
   >
   >> No, using the full length is necessary.  Using a key length less
   than the
   >> full length of the message is very dangerous.
   >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.
                Jim Bell