Column Ciphers

Column Ciphers, or Poem ciphers have been in use by the intelligence services for some time.

Like one time ciphers they require shared knowledge of a code – but in this case the code isn’t used to painstakingly encode every single letter but used to create a column cipher.

How do you make column ciphers?

 The first step in creating a column cipher is to decide on the word you plan to use.  Intelligence agents will often use a long word from a book, which has been agreed upon, or a long word from a memorised poem.

Popular poems of the age were often used, but as they were published, it meant the opposition could easily decode the messages.  Eventually the intelligence services created poetry of their own they would memorise.  That way the code word could never be learned as the original source poem wasn’t published.   READ MORE HERE

Once you’ve picked your word you then need to decide on your message.  In this case we’ll use:

“Sometimes I hate ciphers”


Write the message (ignoring all spaces or using a hyphen for the spaces) into the grid.  The code word dictates the number of columns in  the grid.

Any spare squares should be filled with either a hyphen or a letter – it’s very much personal choice.

Now you need to number your code word, giving the number 1, to the letter which appears first in the alphabet, and the number 2 to the second letter.  In our case, A is the first letter, and as there is no B in our code word, C is our next letter.

Once you’ve numbered your letters you can rearrange the code word into alphabetical order.

Encoding and decoding the text would be easier if we used a word without repeating letters.  But if you assume the first letter of the pair will be the first letter numbered, you can still work it out!

Once the columns are rearranged to match the rearrangement of the code word you now have two ways to provide the code to your handler.

The traditional way is to read the code horisontally, so your message would be:


But you can also be sneaky and read vertically providing the message as:


So long as both the encoder and the receiver know which way the codes are being provided then they will get the right answer.  But you may find you need to try both methods to see which works for your message!

(HINT: If it’s a vertical read, then you really need to know how long the message is in order to work out how many rows you need to write before you move to the column, so you will want to count the characters in the message and divide the number by the number of letters in the code word to give you the right number of rows.)


Extra sneaky?

It was very common for secret agents to double encode messages, using one word to encode the initial message and then another word to re-encode the message. 

This works best if the two code words are of different lengths.

So keep an eye on your coded messages.  If at first you don’t succeed, you may need to find a second code word!

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