Break the Enigma code

Welcome to ECHQ!

The competition is now CLOSED - here is the solution.

Stage One

The first stage involves the shaded boxes and the right column. The solution for the second row, 17, is provided as a lead. The shaded boxes on each row represent a number in binary, so the first row is 01110, the second is 10001, and so on.

These numbers are then converted to decimal and written into the right column as so:

Stage Two

The second stage takes the numbers from the first stage and uses them to decrypt the letter sequences. Again, each row is worked on separately, but it is best to start work on the first row, as it can be assumed a whole word, or the start of a word will appear once the correct decryption method has been applied.

The encryption method used here is a  Caesar cipher, which shifts every letter of the alphabet by a certain number of positions, known as the key. The key for each row is provided by the numbers from the first stage. Here, the letters have been shifted to the right. However, to reverse the encryption, the key has to be subtracted from 26, or you reverse the direction of the shift, to the left. Spaces and symbols are left as they are.

Stage Three

The third stage takes the decrypted text from the second stage, which poses a question, when you put the rows of letters together:

CODENAME FOR WWII SIGINT?

You can just Google this as-is, and you'll probably get the answer fairly easily, but expanding it out, it is asking for the code name used to refer to World War II signals intelligence (often shortened to SIGINT).

The answer is  ULTRA, which can be found on a number of pages, such as  good ol' Wikipedia.

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