Lesson Three Code makers and breakers

Teachers’ Materials Code Makers and Breakers Lesson Plan Further Information

Lesson Materials and Enigma images Codes to Break

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21 Lesson Three: Codemakers and breakers

AIM OVERVIEW To explore the activity of spies and Students will discover the history of code breaking and its significance on the use of code breaking from events such as the Cuban missile crisis. They will be able to learn how code World War Two – the Cuban missile breaking works, and create their own codes. The lesson will enable crisis and beyond. students to consider the moral dilemmas of code breakers. The class will examine code breakers’ legacy. Students can debate the need for secrecy, intelligence gathering and security in the context of the modern world. LESSON OUTCOMES All students will be able to explain EQUIPMENT NEEDED the origins of code breaking and - Pens how codes work. - Timeline of Cuban missile crisis (page 12) - List of codes to break Some students will be able to - Code breakers PowerPoint (online) evaluate the challenges faced by - Countdown clock code breakers during the Cuban missile crisis. SUGGESTED TIME This is a one hour lesson, but can de differentiated to run over a period of A few students will be able to two lessons examining each activity in more detail. consider the legacy of code breaking and its impact on the ROOM LAYOUT modern world. - For group work. - First activity needs space for students to form a ‘debate’ line. CONCEPTS TO EXAMINE Code breaking, secrecy, prejudice SKILLS and discrimination, legacy, - Numeracy intelligence. - Literacy - ICT - Enquiry - Cooperation and team work

22 INSTRUCTIONS Starter Using Code Breakers PowerPoint teacher to use the debate line slide to consider students’ views of secrecy. Pose the question to the students ‘Does secrecy protect peace?’ If they think it protects peace they stand on one side of the room, if they think it doesn’t protect peace they stand on the other side of the room. If they are somewhere in the middle – they stand somewhere in the middle.

Teacher to then encourage students through questioning to explain why they have the opinion that they do – make sure an appropriate number of responses from each side of the viewpoint is examined.

Main activities Put a picture of Alan Turing or Gordon Welchman on the board. Ask students who they think they are. Then put a picture of the on the board – ask students what they think it is. Explain to students using the PowerPoint the historic overview of code breakers at and leading to the Cold War.

Split class into USA and Soviet Union. Roleplay activity with a task: Give students a list of codes to break for USA and codes to break for Soviet Union. (There are two sets of codes to use – these can be used for two sets of groups, or alternatives to extend the code breaking portion of this lesson to fill an hour). They have ten minutes to break each set of codes and must work together in order to do this. Countdown the ten minutes – using a countdown clock.

The majority of codes to crack require knowledge from the further information page – they operate on a Caesar cipher, whereby you replace letters with numbers or other letters.

The first one to break the code and complete the action required by the code is responsible for saving the world – if the codes are not broken within ten minutes the Presidents of the Soviet Union and the USA will launch nuclear weapons at each other and both teams will lose.

At end of activity feedback with the students relating to the problems that they faced as a team, and how they worked together to break the codes – or how they could improve their work in the future.

Students now to create their own codes. They must have a cipher and a way of the code being decrypted when it reaches its destination.

The two teams of USA and Soviet Union stay in place.

Using the timeline of the Cuban missile crisis students pick a significant event in which they would not want the other team to find out about. They then create a code for it.

At the end of the allotted time, students pass the codes to each other and try to break them.

PLENARY Students to discuss what they think the legacy of the code breakers during the Cuban missile crisis is in today’s world. Do they think codes still exist? How do they think codes can be used? Are the use of codes a good think? What do they think could be some of the problems with secrecy and intelligence gathering?

DIFFERENTIATION - For the debate line activity give students prompt cards to help them discuss the arguments for and against. - Give students part of the cipher for the list of codes - Give students clues to help them break the codes - Give students a cipher to make their own codes - Use computers to make a cipher either to crack the codes or make their own

23 EXTENSION - For the debate line activity, students could be asked ‘Does the use of codes keep our world safe?’ or other questions on this theme. - Students could argue against their own view to improve their debating skills. - Students can discuss the legacy of the code breakers, including Alan Turing and Gordon Welchman

ENRICHMENT - Take students to Bletchley Park on a trip to find out more about code makers and code breakers - Watch a film – to learn more about Alan Turing. - Complete the role play or code breaking activities outside the classroom using props, and creative expression. - Read about Gordon Welchman and the invention of ‘The Cloud’ in computer technology - Make and use QR codes to create other forms of codes, these can be done using students’ mobile phones.

24 Further information: Code makers and breakers

Since human beings were able to communicate they have attempted to obscure information from each other in different ways, in order to keep certain things secret. One way in which to do this is to create a code. Those making the codes are called cryptographers. They give the cipher or way to solve the code to the person who is receiving the message. In this way all the codes made in the same way can be read. Without the cipher the message remains secret unless it is broken. Other people who do not have the cipher consider ways in which to break or ‘crack’ the code. Code breakers who use logic, intuition and come up with complex mathematical systems to uncover the secrets in codes are called cryptanalysts or code breakers.

The Greeks and Romans were some of the first civilisations to use sophisticated ciphers to communicate in secret. The scholar Polybius created a system whereby each letter on a grid would be replaced with a letter from the alphabet in 5x5 grid. A = 1x1 = 2 or N = 3x3 = 9 or T = 4x4 = 16, so the numbers 2, 9, 16 = ANT.

Caesar invented a cipher that shifted the letters of the alphabet by a certain number of letters or numbers i.e. A = 2, B = 3, C = 4 or A = B, B = C, C = D. The more complicated the shift of letters/numbers the more challenging the cipher and the more difficult it is to break the code. These two systems have formed the basis of many codes throughout history.

Modern code makers and breakers Codes continued to advance in a similar way as this until the invention of the telegraph machine and Morse code. This meant that nations were now able to transmit codes across large distances and transmit messages to each other easily in times of war. However, the codes that they created had to become more complicated as anyone could listen in and try to work out the cipher for these messages. Codes made by machines started to become more popular as technology improved, as these codes enabled complicated ciphers to be created.

To help cryptanalysts in deciphering messages, cipher machines were developed. One of the oldest of these was created in the 15th century and called the Alberti Disc. It helped code breakers by using two discs on top of each other that could be turned to find the corresponding letter. One of the most famous cipher machines was the Enigma machine made by the Germans the 1920s. This machine looked like a typewriter, but each press of a button indicated a lighted letter. The machine used complex wiring and rotors to create a different letter each time. Without the cipher these machines were almost impossible to crack as they were using so many millions of different letter combinations. In 1932 the first Enigma machine cipher was broken by the Polish General Staff’s . They were able to do this by receiving intelligence about aspects to do with the cipher, and create a machine to crack the code. The Enigma machine was then improved upon and new parts were added to make the code more complicated to crack.

Alan Turing In World War Two the Germans were using Enigma to transmit messages between their forces. The British had previously set up the Government Codes & Ciphers School which Alan Turing had joined. Alan had some ideas about how to decipher the now very complicated Enigma machine if intelligence could be received relating to parts of the code that were similar. Alan Turing created a new Bombe machine and from this the British were able to crack the Enigma machine, and make significant progress in the war. Alan Turing and his team of code breakers are credited with shortening the overall length of World War Two. After World War Two, Prime Minister Churchill asked for the information relating to the discovery of the Enigma codes to be kept secret. Government Codes & Ciphers School became the Government Communications Headquarters (GCHQ). Alan Turing was not recognised for his work, and due to his sexuality, was sentenced to be chemically castrated. He committed suicide in 1954 just before his 42nd birthday. In 2009 Prime Minister Gordon Brown apologised for the appalling treatment of Turing and in 2013 he was posthumously pardoned.

Code breakers in the Cold War GCHQ, Mi5, Mi6 and their counterparts in America, the Central Intelligence Agency were very active in the Cold War attempting to uncover secrets transmitted and communicated between the USSR and its allies.

25 Intelligence gathering is now related to multiple aspects of their work, and the data gathered from both codes and satellites images led to the escalation in the Cold War of the Cuban missile crisis. Mixed messages and a lack of clear communication resulted in some misunderstandings that could have potentially led to the end of the world as we know it.

The internet and ‘The Cloud’ that we use today are a result of the work that mathmaticians like Gordon Welchman carried out during the Cold War.

Cryptographers and cryptanalysts still work to make and break codes but now have the ability to use complex computer programmes to assist. They would say that there is no unbreakable code, just codes that have yet to be broken.

Alan Turing Gordon Welchman

The Enigma Machine Turing’s Bombe that broke the code

26 Codes to break Make sure to give each part of the codes to students to ensure that they will be successful in breaking them. The codes can also be differentiated by providing clues. The ciphers for the answers and the answers themselves can be found at the end of each country set. Do not give these to the students unless you wish to reveal the answers to them. Each word is part of an action that the students must complete to win the game. There are two sets of codes for two countries. This enables two rounds or 4 groups.

USA – Part A: No answers 1st word Code to break: 19, 1, 25

1 2 3 4 5 6 7 8 9 10 11 12 13

A B C D E F G H I J K L M

14 15 16 17 18 19 20 21 22 23 24 25 26

N O P Q R S T U V W X Y Z

2nd word Code to break: 14, 10, 20, 20, 10, 13, 6

1 2 3 4 5 6 7 8 9 10 11 12 13

A B C D E F G H I J K L M

14 15 16 17 18 19 20 21 22 23 24 25 26

N O P Q R S T U V W X Y Z

3rd word Codeword: Bay of Pigs Code to break: UD

A B C D E F G H I J K L M

B A Y O F P I G S

N O P Q R S T U V W X Y Z

27 4th word Codeword: Hotline Code to break: YQNL

A B C D E F G H I J K L M

N O P Q R S T U V W X Y Z

H O T L I N E

5th word Codeword: Time to hurry up, the Soviet Union is winning the arms race. Everyone must support the new atomic age. Atom bombs at the ready. Communists can not rule! Haven't you heard they are getting closer? Expansion of the Soviet Union must be stopped. Ready for nuclear annihilation? USA – Part B: No answers

1st word Code to break: 4, 15, 15

1 2 3 4 5 6 7 8 9 10 11 12 13

A B C D E F G H I J K L M

14 15 16 17 18 19 20 21 22 23 24 25 26

N O P Q R S T U V W X Y Z

2nd word Code to break: 8,16, 22, 7, 24,19

1 2 3 4 5 6 7 8 9 10 11 12 13

14 15 16 17 18 19 20 21 22 23 24 25 26

28 3rd word Codeword: Disarm Code to break: JBVI

A B C D E F G H I J K L M

N O P Q R S T U V W X Y Z

4th word Codeword: Diplomacy Code to break: XPTSP

A B C D E F G H I J K L M

N O P Q R S T U V W X Y Z

5th word V l V

AB CD EF ST GH IJ KL UV WX MN OP QR YZ

29 USA – Part A: Answers for teachers 1st word: SAY . Match number to get the correct letter 2nd word: MISSILE . Minus 1 from the number to get the correct letter 3rd word: TO . Write in the alphabet in order starting at J. If the letter has already been taken in the code word then miss that letter out and enter the following letter instead. 4th word: YOUR . Enter the alphabet starting with A in A. If the letter in the alphabet appears in the code word ‘Hotline’, skip this letter and carry on to the next letter in the alphabet that does not appear in ‘Hotline’. 5th word: TEACHER . Take the first letter of each sentence.

1st word

1 2 3 4 5 6 7 8 9 10 11 12 13

A B C D E F G H I J K L M

14 15 16 17 18 19 20 21 22 23 24 25 26

N O P Q R S T U V W X Y Z

2nd word

1 2 3 4 5 6 7 8 9 10 11 12 13

A B C D E F G H I J K L M

14 15 16 17 18 19 20 21 22 23 24 25 26

N O P Q R S T U V W X Y Z

3rd word A B C D E F G H I J K L M

B A Y O F P I G S C D E H

N O P Q R S T U V W X Y Z

I K L M N Q R T U V X Y Z

4th word

A B C D E F G H I J K L M

N O P Q R S T U V W X Y Z

U V H O T L I N E W X Y Z

30 USA – Part B: Answers for teachers

1st word: ALL . Minus 3 to the number to get the correct letter 2nd word: SKETCH . Enter the letters in alphabetical order but backwards starting with entering A under 26. 3rd word: FIVE . Put code word in to cypher so D of Disarm equals A. Then enter the alphabet. If a letter is taken in the code word then enter the next letter in the alphabet. 4th word: PEACE . Enter the code word backwards so D for Diplomacy equals Z on the grid. Then enter the rest of diplomacy backwards and then the alphabet starting with B underneath Q. 5th word: SIGNS . The symbols correspond to the borders around the letters. If the symbol has a dot then it’s the second letter in that duo of letters.

1st word

1 2 3 4 5 6 7 8 9 10 11 12 13

A B C D E F G H I J K L M

14 15 16 17 18 19 20 21 22 23 24 25 26

N O P Q R S T U V W X Y Z

2nd word 1 2 3 4 5 6 7 8 9 10 11 12 13

Z Y X W V U T S R Q P O N

14 15 16 17 18 19 20 21 22 23 24 25 26

M L K J I H G F E D C B A

3rd word A B C D E F G H I J K L M

D I S A R M B C E F G H J

N O P Q R S T U V W X Y Z

K L N O P Q T U V W X Y Z

31 4th word A B C D E F G H I J K L M

Z X W V U T S R Q N K J H

N O P Q R S T U V W X Y Z

G F E B Y C A M O L P I D

5th word

AI QYV l V l l BJRZl CKSV

DLl l TVl

EMUV

l l l

FNVV GOWV V l HPl Xl

32 Soviet Union – Part A: No answers

1st word Code to break: 20, 5,12, 12

1 2 3 4 5 6 7 8 9 10 11 12 13

A B C D E F G H I J K L M

14 15 16 17 18 19 20 21 22 23 24 25 26

N O P Q R S T U V W X Y Z

2nd word Code to break: 21, 6, 2, 4, 9, 6, 19

1 2 3 4 5 6 7 8 9 10 11 12 13

A B C D E F G H I J K L M

14 15 16 17 18 19 20 21 22 23 24 25 26

N O P Q R S T U V W X Y Z

3rd word Codeword: Atomic Code to break: BLI

A B C D E F G H I J K L M

A T O M I C

N O P Q R S T U V W X Y Z

33 4th word Codeword: Power Code to break: RQTD

A B C D E F G H I J K L M

N O P Q R S T U V W X Y Z

P O W E R

5th word Codeword: My, my – time is starting to run out. Isn't it time we stopped these evil capitalists? Space race has begun. So we must work together. Imperialist Americans must be stopped! Let's get to the moon first! Everyone must support the new atomic age.

Soviet Union – Part B: No answers

1st word Code to break: 7, 21, 4, 26

1 2 3 4 5 6 7 8 9 10 11 12 13

A B C D E F G H I J K L M

14 15 16 17 18 19 20 21 22 23 24 25 26

N O P Q R S T U V W X Y Z

2nd word Code to break: 11, 22, 26, 24, 22

1 2 3 4 5 6 7 8 9 10 11 12 13

14 15 16 17 18 19 20 21 22 23 24 25 26

34 3rd word Codeword: Pacify Code to break: TFOGQNT

A B C D E F G H I J K L M

P A C I F Y

N O P Q R S T U V W X Y Z

4th word Codeword: Truce Code to break: I J

A B C D E F G H I J K L M

N O P Q R S T U V W X Y Z

E C U R T

5th word l l l

AB CD EF ST GH IJ KL UV WX MN OP QR YZ

35 Soviet Union – Part A: Answers for teachers

1st word: TELL . Match number to get the correct letter 2nd word: TEACHER . Minus 1 from the number to get the correct letter 3rd word: THE . Write in the alphabet in order starting at G, entering B. If the letter has already been taken in the code word ‘Atomic’ then miss that letter out and enter the following letter in the alphabet instead. 4th word: WORD . Enter the alphabet starting with A in A unless it appears in ‘Power’. Skip this letter and carry on to the next letter in the alphabet that doesn't appear in ‘Power’. 5th word: MISSILE . Take the first letter of each sentence.

1st word

1 2 3 4 5 6 7 8 9 10 11 12 13

A B C D E F G H I J K L M

14 15 16 17 18 19 20 21 22 23 24 25 26

N O P Q R S T U V W X Y Z

2nd word

1 2 3 4 5 6 7 8 9 10 11 12 13

A B C D E F G H I J K L M

14 15 16 17 18 19 20 21 22 23 24 25 26

N O P Q R S T U V W X Y Z

3rd word

A B C D E F G H I J K L M

A T O M I C B D E F G H J

N O P Q R S T U V W X Y Z

K L N P Q R S U V W X Y Z

4th word A B C D E F G H I J K L M

A B C D F G H I J K L M N

N O P Q R S T U V W X Y Z

Q S P O W E R T U V X Y Z

36 Soviet Union – Part B: Answers for teachers

1st word: DRAW. Plus 3 to the number to get the correct letter. 2nd word: PEACE . Enter the letters in alphabetical order but backwards starting with entering A under 26. 3rd word: SYMBOLS . Put code word in to cypher so P of Pacify equals A. Then enter the alphabet. If a letter is taken in the code word then miss it out and enter the next letter in the alphabet. 4th word: ON . Enter the code word backwards so T for Truce equals Z on the grid. Then enter the rest of Truce backwards and then the alphabet starting with A underneath U. If a letter is taken in the code word, miss it out and enter the next letter in the alphabet. 5th word: PAPER . The symbols correspond to the borders around the letters. If the symbol has a dot then it’s the second letter in that duo of letters.

1st word

1 2 3 4 5 6 7 8 9 10 11 12 13

A B C D E F G H I J K L M

14 15 16 17 18 19 20 21 22 23 24 25 26

N O P Q R S T U V W X Y Z

2nd word

1 2 3 4 5 6 7 8 9 10 11 12 13

Z Y X W V U T S R Q P O N

14 15 16 17 18 19 20 21 22 23 24 25 26

M L K J I H G F E D C B A

3rd word

A B C D E F G H I J K L M

P A C I F Y B D E G H J K

N O P Q R S T U V W X Y Z

L M N O Q R S T U V W X Z

37 4th word

A B C D E F G H I J K L M

Z Y X W V S Q P O N M L K

N O P Q R S T U V W X Y Z

J I H G F D B A E C U R T

5th word

AI QYV l V l l BJRZl CKSV

DLl l TVl

EMUV

l l l

FNVV GOWV V l HPl Xl

Now get students to design their own codes! Use the above ciphers or they can make their own.

38