The Grille Cypher

  • The Grille Cipher
    The Grille Cipher falls into the Transposition Cipher category. A 
    transposition cipher is a plaintext message which is manipulated in such 
    a way as to display a secret cipher text within it. For a good example, 
    I refer to the movie Red Dragon, part of the Hannibal series. Hannibal 
    writes letters to a newspaper editorial column, which Red Dragon then 
    reads, and using a grid, can select only the words of importance...
    It is important to note that this is not a computer based for of 
    encryption. It is all done on paper. There is no algorithm that can 
    decode a grille ciphered message. It is interesting to note that it was first used and developed around 1550 AD.
    Ok, now that we know that, I will show you how to make secret messages 
    for whatever purpose you choose. Be it sending love notes in class, or 
    correspondence with your hired hitman ;)
    Lets make us a plain sounding message:
    I think the flowers
    in spring are worth
    a moment, to have
    a sniff and take in
    the wonders of nature.
    Life is not long enough
    to waste hours beating
    around silly shops.
    Ok, so thats our rather random message that would mean nothing special 
    to the average Joe that picks it up... But, if you had a grid that 
    looked like this:
    | |_|     _                      |
    |         |_|                     |
    |              _                  |
    |   _        |_|                 |
    |  |_|   _                    _ | 
    |_      |_|             _   |_||
    |_|         _          |_|      |
    You or the person you are communicating with would take this grid, place 
    it over the text and the gaps would highlight the following letters:
    t + a + k + e + o + u + t + b + u + s + h
    which is made neater into the message
    "take out bush".
    The perfect way to hide a very illegal, criminal message in an open area 
    without anyone suspecting you. This form of encryption is not used any 
    more except for puzzles and maybe the lame computer puzzle game, but 
    they did serve their purpose many years ago. If you want to be different 
    and basically guarantee confidentiality, go ahead and use this method 
    because no-one bar the most determined cryptographer in the world will 
    bother to decrypt your message :)
    I hope this has been an interesting tutorial, and that it helps develop 
    your understanding and comprehension of some of the possible encryption 
    techniques available.
    Happy Cracking!
    [Ask the experienced, not the learned]