Cryptography 101
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The document provides an overview of basic cryptographic concepts and various coding techniques, including definitions for terms such as cipher, encryption, and plaintext. It presents several simple code examples and challenges to engage readers in practicing code-breaking skills, including backward writing, number substitution, and different historical codes like Caesar's and Vigenère cipher. Additionally, it hints at modern cryptography techniques like frequency analysis and describes how to create and decode messages, culminating in a series of code-breaking challenges for the reader.
Cryptography 101
- 2. The vocabulary of codesAnagram – letters of a word rearranged to say something else
- 3. bilateral – a code containing just 2 symbols
- 4. Cipher – a code in which each letter or number is represented by another letter or number
- 5. Code – the general term for any system that changes a message to make it harder or easier to understand
- 6. Cryptography – the art of writing coded messages
- 7. encryption – the act of concealing something by turning it into code
- 8. hieroglyphics – coded picture writing
- 9. key – the solution that allows you to decipher a coded message
- 10. Plaintext – the original message
- 11. 3 simple codes to warm you up!
- 12. 1: Reverse Codes
- 13. Full reverseDEHCTAW GNIEB SI ESUOH EHT EDISNI YATSIndividual wordsYATS EDISNI EHT ESUOH SI GNIEB DEHCTAW Letter pairsTSYA NIISED HTH EUOES SI EBNIW GTAHCDE
- 14. WEOL RDKD FIR MOEMHTT HO ET OEUDTIS
- 15. WORK FROM THE OUTSIDE TO THE MIDDLE
- 16. 2: Number Codes
- 17. A – 1, B – 2 , C – 3 etcJOT = 10 / 15 / 20
- 18. 20 8 5 / 19 5 3 18 5 20 / 6 9 12 5 19 /1 18 5 / 9 14 / 20 8 5 / 19 1 6 5
- 19. THE SECRET FILES ARE IN THE SAFE
- 20. 3: Vowel Codes
- 21. A E I O U
- 22. YUAR SICRIT PERCIL WOLL ERROVI UN MUNDEY MURNONG
- 23. YOUR SECRET PARCEL WILL ARRIVE ON MONDAY MORNING
- 24. Simple COMBINATION CodesReverse codesNumber codesVowel codes
- 25. UNWRCOSHHCUUL
- 26. UNWRCOSHHCUULHint – 2 stage process using pair reversal and vowels
- 27. UN WR CO SH HC UU LON WR CI SH HC OO LNO RW IC HS CH OO L
- 28. The code breaker’s challengeThere 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!
- 29. The code breaker’s challengePart 1A 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:W R O T I U A T T H I E L P H E B I T
- 30. Greek Codes
- 32. Aeneas’ light hole code
- 34. A = 11, B = 12, S = 43, Y = 54
- 35. 34 45 42 / 13 34 51 15 42 / 24 43 / 12 31 34 52 33 / 42 15 44 45 42 33 / 44 34 /12 11 43 15 / 11 44 / 34 33 13 15
- 36. Y O U R / C O V E R / I S / B L O W N / R E T U R N / T O /B A S E / A T / O N C E
- 37. The code breaker’s challengePart 2After 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’
- 39. Caesar’s code
- 40. A B C D E F G A B C D E F G Letter shift version (3)KHOOR IHOORZ FRGH EUHDNHUV
- 41. Keyword versionC FK F TEFSBEP WCTB F QBCLY BEFH !
- 46. The code breaker’s challengePart 3Your 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:YPLQQ / LAA / SDO / HOSSOPQ / CJ / SDO / JOWS / SDPOO / YLBOEPOKGOPQ / YDKHHOJRO / KJQVOPQ
- 47. Written below this are what appear to be six random words:ComputerSoftwareTerminalKeyboardHackerMouse
- 49. Bacon’s Bilateral codea 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 BABBBEvery ‘marked letter’ represents ‘B’Every ‘unmarked’ letter represents ‘A’Marking can include – underlining, italics, size differences, capitalisation, pin pricking, invisible ink
- 50. How wonderful it was to see you last weekend. I hope you enjoyed our day in London as much as I did.Howwonderful itwas to see you last weekend. Ihope youenjoyed our day in London as much as I did.
- 51. Howwonderful itwas to see you last weekend. Ihope youenjoyed our day in London as much as I did.BabbaabbabbaabbaaaaabaaaaaabaaabaaaAbbaaaaabbaaaaaabbaaaabbaaabaabaaaaaaaaYou are in danger
- 52. The Vigenere tableau1) Choose a keyword : MANCHESTER2) Above your message write out the keyword repeatedly3) Using the plaintext on the ‘x’ axis of the tableau and the keyword letters on the ‘y’ axis, compose the coded message(without the keyword, this is almost unbreakable)
- 54. SENDMANCHESTER
- 55. EEA
- 56. EEAF WLBPYKLW
- 57. To decipher, you simply reverse the rules by writing the keyword repeatedly above the coded messageThen take the first letter of the keyword on the ‘x’ axis and follow the tableau down until it meets the code letterRead across to the ‘y’ axis to identify the original plaintextSE
- 58. Use the Vigenere tableau to crack these 10 words – when considered together you will be able to identify 5 popular TV soap operasKeyword = SOAPTFODCSKANGOKHKHRTWHFSIVZPOJJGUCRDFOTXGBSBDKWDTZCLAQZCMT
- 60. Frequency tablesE T A O N R I S H D L G C M U F Y P W B V K X J Q ZSingle letter words - I or A in EnglishDouble letters tend to be – B D E F G L M N O P R S TLook out for short words from which you can make educated guessesCombine deduction, common sense, patience and guess work!Above all else – keep your key up to date
- 61. The code breaker’s challengePart 4Someone 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.
- 62. CODE 1: P OMUPNQMU GPK AN SATTUH AHNATU OSU JPDOMUU HUPM OSU WUNOUMH WPFF JR OSU RAUFTClues: O = T, A = I, G = M, N = S- -------- --- -- ------ ------ --- --- -------- --- ------- ---- -- --- -----
- 63. CODE 2: TDMRM FS C SMNRMT PCSSCBM IMTWMML TDM SKUBBJMRS NCVM CLE TDM OJE DOUSMClues: The letters from P-Z have not changed----- -- - ------ ------- ---------- --------- ---- --- --- --- -----
- 64. CODE 3: JSST JS DK TCS QNNJ ISCDKM TCS RSLQST MNNQ DK TCS INNGLFRS FKM JFGS RUQSKNINMY RSSR YNUClues: F = A, Q = R---- -- -- --- ---- ------ --- ------ ---- -- ----------- --- ---- ---- ------ ---- ---
- 65. CODE 4: TDM WORE YOU LMME TO WRFTM EOWLCS TDM CLSWMR DMRM FS DOTClues: E = D--- ---- --- ---- -- ----- ---- -- --- ---------- -- ---
- 67. The code breaker’s challengePart 5You 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…
- 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.
- 69. Crossword Codes
- 70. 1) Both sender and receiver must have the same blank crossword.2) The message is written from left to right in the blank squares.3) The code is then achieved by copying out the text again, but this time working vertically.4) To decipher the message it must be written into the blank grid vertically but read off horizontally.
- 71. This method of creating a code is simple but very effective HCOEY TRSC HOEDBET AI IDTUFV SIEME MNT EOGIPVF TAE FCSLRE
- 72. The code breaker’s challengePart 6A 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: 20 / 9 / 13 / 5 / 19On the other side it says:LNTSWTES CSNE OAFTFHGAR NIIEI GTONCS RGHENF ATAAL TIRHTLTSY UGHX OEIRHLIW
- 73. Examining the postcard more closely you find a clue written underneath the stamp: the word ‘newspaper’.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.
- 74. Daily Telegraph
- 75. The Times
- 76. Daily Mirror
- 77. Daily Express
- 78. Typewriter codes & the history of QWERTY
- 79. One to the leftOne to the rightOne aboveOne belowAlternate between one or more of these variations with key
- 80. QGLR AIYBS SIWA L NIBJWT VINV NLJW QGWB UR WZOKISWA?
- 82. HWHMMMMK !
- 84. The code breaker’s challengePart 7You 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:DVLWW LRR BYC OQWB WCFCH OCBBCVW
- 85. Sherlock Holmes & the dancing men
- 87. The code breaker’s challengePart 8You 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.Clues: How do letters usually start? Who is the letter to and from?
- 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.Upon opening it, you discover another set of dancing men – could this bring you one step closer to cracking the master code?
- 90. The code breaker’s challengePart 9This 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>Clues: The code is hiding a 7 letter word.
- 91. Newspaper’s bill £5Dry cleaning £8Take away pizza £7Light bulbs £3Fridge magnet £2Car-park token £2Cinema ticket £5
- 92. The final code breaker’s challenge!
- 94. QR codes
- 97. The Vaudeville telepathy act
- 98. The GReY code
- 99. Pick a card...any card