Cracking Codes
XZM BLF FMWVIHGZMW GSRH HVMGVMXV – it may look like a foreign language or simply nonsense but these letters are an encoded message. Read on to find out what it says.
Codes have been used for centuries to keep information secret. Codes replace one word with another or mix the letters up. They may also use symbols instead of letters or numbers.
The Roman emperor Julius Caesar used a very simple code by moving each letter of the alphabet along three letters, so A=D, B=E, C=F and so on. In his code, ‘hello’ is ‘ebiil’.
Spoken codes, such as Pig Latin, usually keep the original letters of the words but change their order and add a suffix. ‘Bananas’ might change to ‘ananas-bay’.
Enigma
During World War Two the Germans used the Enigma machine to send encoded messages. The machine looked like a typewriter with a second set of letters above the keyboard, arranged in the same order as the keyboard.
Scramblers in the machine encoded the messages typed in. When a letter on the keyboard was pressed, a different letter on the top alphabet lit up. The operator wrote down the coded letters and then sent the coded message by telegraph, using Morse code.
To keep their messages secret, the settings on the Enigma machine changed daily. A codebook told the operators which code to use. The person receiving the message needed a machine set up with the same code as the sender.
But the British, with the help of Polish code breakers, had worked out the Enigma code before the war started. They kept this secret and they intercepted messages without the Germans knowing.
Not So Secret
Not all codes are used to send secret messages. Some codes, such as the dots and dashes of Morse code or the squiggles of shorthand, are used by people all over the world. Because anyone can learn and use these, they are not so good if you want to send a secret message.
Some codes are meant to send a clear message. Blackbeard, the notorious eighteenth century pirate, flew a flag from his ship showing a skeleton with devil’s horns stabbing a heart. That certainly wasn’t saying ‘Welcome aboard’!
Crack the Code
When it comes to trying to break a code, it helps if you know how often letters are used. In English, the four most used letters are E, T, O and A, and the most common double-letter vowels are OO and EE.
By the way, if you want to read the coded message at the start, reverse the alphabet, so A=Z, B=Y, C=X and so on. Have a go at making up your own code but make sure you give someone the key so they can decode your messages.
Based on the article by Caroline Christie