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Codes and Ciphers

Codes and Ciphers. By the end of this session you will be able to:. Decode messages using different ciphers. Solution:. By the end of this session you will be able to:. Round 1- Texting Challenge. Examples 927 WAS/WAR 2628 BOAT/COAT 4483 GIVE/HIVE. Round 1- Texting Challenge.

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Codes and Ciphers

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  1. Codes and Ciphers By the end of this session you will be able to:

  2. Decode messages using different ciphers Solution: By the end of this session you will be able to:

  3. Round 1- Texting Challenge • Examples • 927 • WAS/WAR • 2628 • BOAT/COAT • 4483 • GIVE/HIVE

  4. Round 1- Texting Challenge “9428 36 968 2255 2 74337 9484 66 5347?” “2 25683!”

  5. Round 1- Texting Challenge Solution: “9428 36 968 2255 2 “What do you call a 74337 9484 66 5347?” sheep with no legs?” “2 25683!” “A cloud!”

  6. Example Welcome to Leeds University welcometoleedsuniversity 24 letters long = 6×4 or 2×12 or 3×8 or 2×12 or 1×24 So write: Round 2- Transposition Challenge

  7. Going the other way round: ckatsoenaadekifepdlesbesr 25 letters= 5×5 So write: Round 2- Transposition Challenge

  8. Example cbkhenlroreedwdtderlwowweaspirao 32 letters long= 1×32 or 2×16 or 4×8 So write: Round 2- Transposition Challenge

  9. Challenge trmsimhlatsledld1owslo5nosegcg Round 2- Transposition Challenge

  10. Round 2- Transposition Challenge

  11. Round 2- Transposition Challenge • Challenge trmsimhlatsled1owslo5nosegcg • Answer: The world’s smallest dog is 15cm long

  12. Round 3- Pencil Code

  13. Answer- This code was used 2500 years ago by the Spartans in Ancient Greece. Round 3- Pencil Code

  14. This would be a good time to try to earn some bonus points with the Number Phrase Round! Refreshment Break

  15. Practise Questions 00010 11111 10011 00101 Round 4- Binary Challenge

  16. Round 4- Binary Challenge Answer: Computers view everything as ones and zeroes!

  17. Round 5- Error Checking Challenge

  18. error_checking_example.doc

  19. Error Checking

  20. Image from the 2006 Royal Institution Christmas Lectures

  21. Image from the 2006 Royal Institution Christmas Lectures

  22. The Final!Frequency Analysis

  23. The most frequent two-letter words are OF, TO, IN, IT and IS The most frequent three letter words are THE, AND, FOR, ARE and BUT Half of all English words begin with A,O,S,T or W Other handy hints when cracking codes:

  24. The best code crackers won’t give up and always want to find the answer. Often there is a reward for those who succeed. The Solution !

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