Produced in conjunction with Tom Briggs, Education and Outreach Officer at Bletchley Park.

A Series of Unfortunate Events. In this clip, Klaus uses the approximate thickness of his relative’s arm and the shading on the snake to send a message to him about the evil Count Olaf who is disguised as Gustav.

… is nothing new. In the 3 rd Century BCE the Ancient Greeks used… … to send secret messages during military campaigns. Picture:

Use the strip of paper to come up with your own scytale code for your partner to solve. You could wrap it around your arm, a pencil or a glue stick.

… Julius Caesar used a system of shifting the alphabet three spaces to the left to hide messages to his armies. We call this a Ceasar Shift Cipher.

FDHVDU UXOHV Caesar Rules Answer

… has been used as the basis for many more complicated ciphers. This Vigenere grid contains every possible Caesar shift, and uses a keyword to switch between them when encrypting information.

The key is ‘solve’ What command is given in the following message? SHEVGC Attack! Answer

… has been a driving force for creating more complicated codes and ciphers throughout history.

… were used during World War I. With mostly static warfare, the codes were fairly simple 2 or 3 letter groups given meanings in codebooks. Ciphers used include Playfair and complicated versions of Vigenere, but were still produced by hand.

… in World War II, and the use of radio rather than fixed telephone cables meant that ciphers had to get more complicated. In 1918 Arthur Scherbius applied for a patent for a rotor-based cipher machine.

… of Cipher machines was born in 1923, and used commercially at first. In 1926 the German Navy began to use Enigma machines. The rest of the German military soon followed.

… allowed ciphers to become much more complicated. There are 25 different usable Caesar shifts, compared to… … nearly 159,000,000,000,000,000,000 possible key settings for a standard Army Enigma machine.

… the British Government Code & Cypher School (GC&CS) began to move to Bletchley Park (now near Milton Keynes). Their mission was to decipher intercepted messages so that intelligence could be gathered, giving the Allied forces the edge in World War II.

… the Nazis added another cipher machine to their arsenal. The Lorenz Cipher Attachment was used for high- level communications.

… were hard to crack, so the Codebreakers invented new machines themselves.

… was designed by Alan Turing in 1939, and refined by Gordon Welchman in It was an electromechanical machine designed to speed up the process of discovering settings used by Enigma operators. By Antoine Taveneaux (Own work) [CC-BY-SA-3.0 ( via Wikimedia Commons

… started work in It was designed by Tommy Flowers to help find key settings for deciphering Lorenz enciphered messages… … and was the world’s first programmable computer!

… have made it much easier to crack codes and solve ciphers… … so encryption has had to get much more complicated… … and the race is on to develop ever cleverer ways of hiding and revealing information!

How does this link to what we’ve just learnt?

Your teacher will distribute codes for you to attempt to crack in your groups. Good luck!

Read the sheet and attempt to crack the code.