The Year 7 girls have a cracking morning

The Year 7 girls have a cracking morning

Year 7 students had an exciting morning learning about coding on Monday 16 October. The girls were joined by Mr James Grime, a mathematician with a passion for cryptography.

Mr Grime asked the girls: ”If you were a spy trying to access a secret code hidden inside a locked box, how would you get in to the box?” The girls were all keen to answer, with a few responding” pick the lock”, ”find the key” and ”break the box”.

Once the girls’ inquisitive minds had been set to work, Mr Grime spoke about code breaking, secret messaging and the history of cryptography, The girls looked at a number of instances of code breaking and secret messaging cases throughout history; Mary Queen of Scots, the Spartans and Al Kindi, for example. Perhaps the most interesting case was the coding method used by Julius Caesar; the ‘Caesar Shift.’ This was a coding method that used the alphabet, moving the letters either backwards or forwards; for example (if you were to shift forward by two), a would become c, b would become d, c would become e, and so on. Although this shifting method has been used in many cases throughout history, it was noteworthy to Caesar because he always shifted the alphabet three times forward when he was sending a secret message.

The highlight of the day for many was to see the original Enigma machine that Mr Grime brought in to school with him, and which he was able to demonstrate to the girls. He showed that the machine even transposed one particular message into a different coded message each time he input the message. For example, when he input the word ‘hello’ the Ls became Y and O. The complex coding machine was used in World War II by the Germans to send coded messages of high importance. The allies knew that it was imperative to crack the code created by this ‘unbreakable’ machine, so a team of the smartest mathematicians was gathered to decipher the code and, in turn, help bring an earlier end to the war. The significant deciphering of the Enigma machine by all those involved at Bletchley Park was said to have reduced the war by two to three years, and saved an estimated 14-21 million lives.

Mr Grime spoke of how Alan Turing and his team spent years trying to crack the Enigma machine. The machine that Turing created to crack the code, the Bombe Machine, worked faster than any human could. In fact, if the code was to be broken by humans, the girls found out that even if 7 billion people were checking all 400 million billion billion possible codes every second, it would still take 2 billion years to figure it out.

After the talk, the girls returned to crack codes of their own in small groups. During the code breaking session, Mr Grime gave each pair of girls a code to crack in around 20 minutes. All deciphered the easiest message, with some even decoding the advanced codes!

The girls had a thoroughly enjoyable and interactive morning and the opportunity to witness such a rare and historically significant machine in action was both exciting and informative.