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The Secret World of Codes and Codebreaking

The enigma project. The Secret World of Codes and Codebreaking. Code : whole words or phases are replaced by a letter or number Cipher: individual letters are replaced with other letters or symbols. Plaintext: normal English Ciphertext: coded English. ACTIVITY 1.

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The Secret World of Codes and Codebreaking

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  1. The enigma project The Secret World of Codes and Codebreaking

  2. Code:whole words or phases are replaced by a letter or number Cipher:individual letters are replaced with other letters or symbols Plaintext:normal English Ciphertext:coded English

  3. ACTIVITY 1 Decipher the ciphertext on the strip of paper. CLUE: You will have to use a pencil. But you don’t use the pencil in the usual way!

  4. Scytale: Used by the Spartans in Ancient Greece 2500 years ago

  5. Scytales must be the same size to be able to decipher a message

  6. Scytales must be the same size to be able to decipher a message

  7. Cipher = Algorithm + Key

  8. Caesar Shift Cipher MISS ELLIS NJTT FMMJT

  9. Caesar Shift Cipher MXOLXV FDHVDU WKH URPDQ JHHCHU VTXDVKHG KLV ZLIH LQ D OHPRQ VTXHHCHU

  10. ACTIVITY 2 Decipher this message. Each plaintext letter has been moved three places forward in the alphabet… MXOLXV FDHVDU WKH URPDQ JHHCHU VTXDVKHG KLV ZLIH LQ D OHPRQ VTXHHCHU 7K H P J

  11. Caesar Shift Cipher Julius Caesar the Roman Geezer Squashed his wife in A Lemon Squeezer!

  12. Caesar Shift Cipher How many possible keys are there with the Caesar Shift Cipher? 25

  13. ACTIVITY 3 How many possible keys are there when you swap each letter of the alphabet with another letter? 400 million billion billion 400 000 000 000 000 000 000 000 000

  14. 400 million billion billion keys 6.5 billion people in the world 31 million seconds in a year If everyone in the world checked one key per second, it would still take 2 billion years to check them all

  15. Mary Queen of Scots and the Babington Plot

  16. One of the messages Mary Queen of Scots sent to Babington

  17. ACTIVITY 4 How would you go about trying to crack this type of cipher when there are a possible 400 million billion billion keys?

  18. An unusual message Today, by radio, and also on giant hoardings, a rabbi, an admiral notorious for his links to masonry, a trio of cardinals and a trio, too, of politicians inform us all of how our country now risks dying of starvation.

  19. ACTIVITY 5 Have a conversation with the person sitting next to you WITHOUT using any words that contain the letter E START NOW STOP!

  20. Al Kindi’s book written in 800 AD

  21. Code Breaking Tips Common letters One letter words Common words Double letters Clues

  22. WW2 Enigma Machine

  23. General Guderian’s Command-post vehicle

  24. Bletchley Park – Government Code and Cipher School

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