The Polybius Cipher

  • The Polybius Cipher
    -------------------
    
    The Polybius Cipher is another type of substitution cipher. It involves 
    using a 5x5 matrix holding all the letters of the alphabet. Yes, so, 
    there are 26 letters in the alphabet and a 5x5 matrix can only hold 25 
    letters. This is a trivial problem. The least used letters are simply 
    paired up. The best options would probably be x and z, so let's put them 
    together.
    
    This will give us the following matrix:
    
     | 1 | 2 | 3 | 4 | 5 | 
    -|---|---|---|---|---|
    1| a | b | c | d | e |
    -|---|---|---|---|---|
    2| f | g | h | i | j |
    -|---|---|---|---|---|
    3| k | l | m | n | o |
    -|---|---|---|---|---|
    4| p | q | r | s | t |
    -|---|---|---|---|---|
    5| u | v | w | y |x/z|
    ----------------------
    
    Ok, now that we have our simple 5x5 matrix, we can start the 
    substitution process. For example, the letter 'a' is 1x1 or x=1,y=1. 
    This can be simplified by 11. Another example, let's take the letter 'n'. 
    This is in the position 4x3 or x=4,y=3. This can be simplified to 43. 
    So, now, let's encrypt a simple message.
    
    I HATE MY WIFE
    42-32-11-54-51-33-45-35-42-12-51
    
    As you can see, I separated the numbers by the symbol '-'. This could be 
    any other symbol or even just a space. Perhaps to confuse and mislead 
    someone, you could use random symbols, just as long as the numbers stay 
    in the correct order or else the message will be misinterpretted. 
    
    Deciphering the message is as easy as as substituting the numbers into 
    the grid. This will give you the corresponding letter.
    
    This is the most simple version. If you wish to secure your 
    messages with someone, jumble up the letters in the grid. As long as the 
    receipient has the exact matrix, they will be able to decipher it. I 
    hope this has been helpful and interesting.
    
    invas10n
    --------
    [Ask The Experienced, Not The Learned]