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# Cryptography 101

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A slideshow used with keystage 3 students which introduces code breaking skills as a fun end of year project

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### Cryptography 101

1. 1. Cryptography 101<br />
2. 2. The vocabulary of codes<br />Anagram – letters of a word rearranged to say something else<br />
3. 3. bilateral – a code containing just 2 symbols<br />
4. 4. Cipher – a code in which each letter or number is represented by another letter or number<br />
5. 5. Code – the general term for any system that changes a message to make it harder or easier to understand<br />
6. 6. Cryptography – the art of writing coded messages<br />
7. 7. encryption – the act of concealing something by turning it into code<br />
8. 8. hieroglyphics – coded picture writing<br />
9. 9. key – the solution that allows you to decipher a coded message<br />
10. 10. Plaintext – the original message<br />
11. 11. 3 simple codes to warm you up!<br />
12. 12. 1: Reverse Codes<br />
13. 13. Full reverse<br />DEHCTAW GNIEB SI ESUOH EHT EDISNI YATS<br />Individual words<br />YATS EDISNI EHT ESUOH SI GNIEB DEHCTAW <br />Letter pairs<br />TSYA NIISED HTH EUOES SI EBNIW GTAHCDE<br />
14. 14. WEOL RDKD FIR MOEMHTT HO ET OEUDTIS<br />
15. 15. WORK FROM THE OUTSIDE TO THE MIDDLE<br />
16. 16. 2: Number Codes<br />
17. 17. A – 1, B – 2 , C – 3 etc<br />JOT = 10 / 15 / 20<br />
18. 18. 20 8 5 / 19 5 3 18 5 20 / 6 9 12 5 19 /<br />1 18 5 / 9 14 / 20 8 5 / 19 1 6 5 <br />
19. 19. THE SECRET FILES ARE IN THE SAFE<br />
20. 20. 3: Vowel Codes<br />
21. 21. A E I O U<br />
22. 22. YUAR SICRIT PERCIL WOLL ERROVI UN MUNDEY MURNONG<br />
23. 23. YOUR SECRET PARCEL WILL ARRIVE ON MONDAY MORNING<br />
24. 24. Simple COMBINATION Codes<br />Reverse codes<br />Number codes<br />Vowel codes<br />
25. 25. UNWRCOSHHCUUL<br />
26. 26. UNWRCOSHHCUUL<br />Hint – 2 stage process using pair reversal and vowels<br />
27. 27. UN WR CO SH HC UU L<br />ON WR CI SH HC OO L<br />NO RW IC HS CH OO L<br />
28. 28. The code breaker’s challenge<br />There are 9 parts to the code maker’s challenge – each step will give you part of a master key which you will need to crack the final code...and win a prize!<br />
29. 29. The code breaker’s challengePart 1<br />A mysterious letter has arrived on your doormat. It has an Egyptian postmark, and very neat, old-fashioned handwriting on the envelope. Inside is a single thin piece of paper, and written on it is a coded message:<br />W R O T I U A T T H I E L P H E B I T <br />
30. 30. Greek Codes<br />
31. 31. The Spartan Scytale<br />
32. 32. Aeneas’ light hole code<br />
33. 33. Polybius grid code<br />
34. 34. A = 11, B = 12, S = 43, Y = 54<br />
35. 35. 34 45 42 / 13 34 51 15 42 / 24 43 / <br />12 31 34 52 33 / 42 15 44 45 42 33 / 44 34 /<br />12 11 43 15 / 11 44 / 34 33 13 15<br />
36. 36. Y O U R / C O V E R / I S / <br />B L O W N / R E T U R N / T O /<br />B A S E / A T / O N C E <br />
37. 37. The code breaker’s challengePart 2<br />After playing with your computer for several hours, you feel it’s time to take a break. You go to get a drink – but when you return, you realise instantly that someone has used the machine while you were away. A strange sequence of numbers has been typed out across the screen, and written beneath is the following message – ‘you’ve been flamed’<br />
38. 38. 142451241415442315<br />1131352311121544<br />243344343511244243<br />113314<br />21312435<br />15111323<br />35112442<br />114234453314<br />
39. 39. Caesar’s code<br />
40. 40. A B C D E F G <br />A B C D E F G <br />Letter shift version (3)KHOOR IHOORZ FRGH EUHDNHUV <br />
41. 41. Keyword version<br />C FK F TEFSBEP WCTB F QBCLY BEFH !<br />
42. 42. Keyword protection<br />
43. 43. The Freemasons’ code<br />
44. 44.
45. 45.
46. 46. The code breaker’s challengePart 3<br />Your computer lets you know that someone has sent you an email. The address f the sender seems to be somewhere in Egypt. The message reads as follows:<br />YPLQQ / LAA / SDO / HOSSOPQ / CJ / SDO / JOWS / SDPOO / YLBOEPOKGOPQ / YDKHHOJRO / KJQVOPQ<br />
47. 47. Written below this are what appear to be six random words:<br />Computer<br />Software<br />Terminal<br />Keyboard<br />Hacker<br />Mouse<br />
48. 48. Renaissance Codes<br />
49. 49. Bacon’s Bilateral code<br />a AAAAA g AABBA n ABBAA t BAABAb AAAAB h AABBB o ABBAB u-v BAABBc AAABA I-j ABAAA p ABBBA w BABAAd AAABB k ABAAB q ABBBB x BABABe AABAA l ABABA r BAAAA y BABBAf AABAB m ABABB s BAAAB z BABBB<br />Every ‘marked letter’ represents ‘B’<br />Every ‘unmarked’ letter represents ‘A’<br />Marking can include – underlining, italics, size differences, capitalisation, pin pricking, invisible ink<br />
50. 50. How wonderful it was to see you last weekend. I hope you enjoyed our day in London as much as I did.<br />Howwonderful itwas to see you last weekend. Ihope youenjoyed our day in London as much as I did.<br />
51. 51. Howwonderful itwas to see you last weekend. Ihope youenjoyed our day in London as much as I did.<br />Babbaabbabbaabbaaaaabaaaaaabaaabaaa<br />Abbaaaaabbaaaaaabbaaaabbaaabaabaaaaaaaa<br />You are in danger<br />
52. 52. The Vigenere tableau<br />1) Choose a keyword : MANCHESTER<br />2) Above your message write out the keyword repeatedly<br />3) Using the plaintext on the ‘x’ axis of the tableau and the keyword letters on the ‘y’ axis, compose the coded message<br />(without the keyword, this is almost unbreakable)<br />
53. 53.
54. 54. SEND<br />MANCHESTER<br />
55. 55. E<br />E<br />A<br />
56. 56. EEAF WLBPYKLW<br />
57. 57. To decipher, you simply reverse the rules by writing the keyword repeatedly above the coded message<br />Then take the first letter of the keyword on the ‘x’ axis and follow the tableau down until it meets the code letter<br />Read across to the ‘y’ axis to identify the original plaintext<br />S<br />E<br />
58. 58. Use the Vigenere tableau to crack these 10 words – when considered together you will be able to identify 5 popular TV soap operas<br />Keyword = SOAP<br />TFODC<br />SKAN<br />GOKH<br />KHRTWH<br />FSIVZPOJJG<br />UCRDFOTXGB<br />SBD<br />KWDT<br />ZCLAQ<br />ZCMT<br />
59. 59. Modern Cryptology<br />
60. 60. Frequency tables<br />E T A O N R I S H D L G C M U F Y P W B V K X J Q Z<br />Single letter words - I or A in English<br />Double letters tend to be – B D E F G L M N O P R S T<br />Look out for short words from which you can make educated guesses<br />Combine deduction, common sense, patience and guess work!<br />Above all else – keep your key up to date<br />
61. 61. The code breaker’s challengePart 4<br />Someone has tucked 4 coded messages inside your bag when you were not looking. The first 3 are written using different codes. The 4th uses the same code as one of the first 3 and contains the answer you need for this part of the challenge.<br />
62. 62. CODE 1: <br />P OMUPNQMU GPK AN SATTUH AHNATU OSU JPD<br />OMUU HUPM OSU WUNOUMH WPFF JR OSU RAUFT<br />Clues: O = T, A = I, G = M, N = S<br />- -------- --- -- ------ ------ --- --- ----<br />---- --- ------- ---- -- --- -----<br />
63. 63. CODE 2: <br />TDMRM FS C SMNRMT PCSSCBM IMTWMML TDM SKUBBJMRS NCVM CLE TDM OJE DOUSM<br />Clues: The letters from P-Z have not changed<br />----- -- - ------ ------- -------<br />--- --------- ---- --- --- --- -----<br />
64. 64. CODE 3: <br />JSST JS DK TCS QNNJ ISCDKM TCS RSLQST MNNQ DK TCS INNGLFRS FKM JFGS RUQSKNINMY RSSR YNU<br />Clues: F = A, Q = R<br />---- -- -- --- ---- ------ --- ------ ---- -- ---<br />-------- --- ---- ---- ------ ---- ---<br />
65. 65. CODE 4: <br />TDM WORE YOU LMME TO WRFTM EOWLCS TDM CLSWMR DMRM FS DOT<br />Clues: E = D<br />--- ---- --- ---- -- ----- ---- -- --- ------<br />---- -- ---<br />
66. 66.
67. 67. The code breaker’s challengePart 5<br />You receive a message at school, telling you to go to the OMR. When you get there you find the following message scrawled on the wall…<br />
68. 68. Sir ArthURConAndoyLeWaS the CreatOr of The wOrlD’sGreaTesTdeTeCtiVeshErlOckholMEs. ConAnDOylE was BORniNedInBurgH, AnD Although HE studied medIcINe, hESOoN turned To WriTInG. Sherlock hoLMEsfiRSTApPEaRed In thE Novel a sTudy In sCarlet, WhiCHwAsNArrateD By HiSfriEnd Dr jOhN h. wAtsoN. thEdetecTIvE soon BEcaMe famous fOrhIsBrilLIaNT skills oFDeDUCtIon, AS WeLL AS fORHiSfIery Character. His arch-ENEmy Was tHEEviL professor MORiArty. Holmes waS So PoPulaR that eVeNafTerhE seemed to FAlL to HiSDeaTh during a FigHtAbovE A wATerfall, cONandOylE was fORCedtOBRInGhiM back AfTeR A hUgEPuBlICoUTcRy. <br />
69. 69. Crossword Codes<br />
70. 70. 1) Both sender and receiver must have the same blank crossword.<br />2) The message is written from left to right in the blank squares.<br />3) The code is then achieved by copying out the text again, but this time working vertically.<br />4) To decipher the message it must be written into the blank grid vertically but read off horizontally.<br />
71. 71. This method of creating a code is simple but very effective <br />HCOEY TRSC HOEDBET AI IDTUFV SIEME MNT EOGIPVF TAE FCSLRE<br />
72. 72. The code breaker’s challengePart 6<br />A strange looking card arrived in the post this morning – addressed to you, with an Egyptian stamp on it. On one side, it has the code: <br />20 / 9 / 13 / 5 / 19<br />On the other side it says:<br />LNTSWTES CSNE OAFTFHGAR NIIEI GTONCS RGHENF ATAAL TIRHTLTSY UGHX OEIRHLIW<br />
73. 73. Examining the postcard more closely you find a clue written underneath the stamp: the word ‘newspaper’.<br />The following grids appeared in national newspapers on the day the card was posted. Fill the correct grid vertically to read off a horizontal message – the answer is a kind of insect.<br />
74. 74. Daily Telegraph<br />
75. 75. The Times<br />
76. 76. Daily Mirror<br />
77. 77. Daily Express<br />
78. 78. Typewriter codes & the history of QWERTY<br />
79. 79. One to the leftOne to the rightOne aboveOne belowAlternate between one or more of these variations with key<br />
80. 80. QGLR AIYBS SIWA L NIBJWT VINV NLJW QGWB UR WZOKISWA?<br />
81. 81.
82. 82. HWHMMMMK !<br />
83. 83.
84. 84. The code breaker’s challengePart 7<br />You are taking your laptop out of the cupboard to work on some homework for school, when you notice a sheet of paper taped to the underside. The printed message reads:<br />DVLWW LRR BYC OQWB WCFCH OCBBCVW<br />
85. 85. Sherlock Holmes & the dancing men<br />
86. 86.
87. 87. The code breaker’s challengePart 8<br />You are visiting a museum at 221B Baker street on a school trip, when you stumble across an old piece of paper. It looks like a coded letter made up of odd looking stick men.<br />Clues: How do letters usually start?<br /> Who is the letter to and from?<br />
88. 88. At school the next day, you are browsing through the library when you come across a folded piece of paper with your name on it, sticking out of an anthology of detective fiction.<br />Upon opening it, you discover another set of dancing men – could this bring you one step closer to cracking the master code?<br />
89. 89. Shopping list codes<br />
90. 90. The code breaker’s challengePart 9<br />This morning you found a list scrawled on the back of one of your exercise books. None of your friends or family has owned up – is this list of purchases as innocent as it looks><br />Clues: The code is hiding a 7 letter word.<br />
91. 91. Newspaper’s bill £5<br />Dry cleaning £8<br />Take away pizza £7<br />Light bulbs £3<br />Fridge magnet £2<br />Car-park token £2<br />Cinema ticket £5<br />
92. 92. The final code breaker’s challenge!<br />
93. 93.
94. 94. QR codes<br />
95. 95. Augmented reality<br />
96. 96.
97. 97. The Vaudeville telepathy act<br />
98. 98. The GReY code<br />
99. 99. Pick a card...any card<br />