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84 CHAPTER 5. MONOALPHABETIC CIPHERS 9. Decrypt the following Aristocrats. A hint has been given. (a) ZJG REGFF ADLH DZRFG AFDRE, EDXG DKA ZXKYFGKDXVH BJKRXKQF RJ YGJO. CQR TEJKF BDVVH RDTFG JZZ. IJEKKL BDGHJK. Hint: R = t. (b) KAHTH FN WJ XLW NJ EMHNNHC KALK NJXH RAJ NKLWC EP AFN CHLKAEHC RJW’K ALFM KAH JDDLNFJW RFKA CHMFIAK. XLTDSN LSTHMFSN. Hint: A = h . (c) E OEB IZ JVEYU KCH KVIRTZ E ZTJVTR IB EBU HRCTV KEU RCEB HBT KCIJC KIWW JHBJTEW IR XVHO RCT FAWGEV. VHGTV DEJHB. Hint: V = r. (d) D QZJSEY ZO D VEGSAX AB TYZGZMK D VEOODKE OA GSDG ZG QDMMAG IE YEDX IL DMLAME ZKMAYDMG AB GSE VEGSAX. BNEGQSEY JYDGG. Hint: X = d. 10. Decrypt the following Aristocrats. (a) IOKVK MVK UKTKVMZ JGGF XVGIKLICGHU MJMCHUI IKYXIMICGH ENI IOK UNVKUI CU LGSMVFCLK YMVA ISMCH (b) EKY HZMJECDZAX US EKY AZUSECHZAE CI JLWWNYS XCEEC CI EKY AXYZ- UHAR HZMJECDZAJK ASSCHUAEUCR (c) CP TEF HALZKCTO ZM QCREFKV CT CV ZPNO TEF FGCVTFPQF ZM KFDJPD- APQO CP TEF ZKCXCPAN HFVVAXFV TEAT HAWFV A VZNJTCZP RZVVCINF (d) MOY DYKP IOJIVJPFEPV ESDOKP LJ E JVFWOYK PFEJIV BGVJ BOFZLJA OJ E IONV LP LK JOP OQPVJ NOJV CM IOJKILOYK VQQOFP DLKK QFLVN- FLIGK 11. During the 1670’s The Chevalier de Rohan was imprisoned under suspicion of treason. While guilty, there was little evidence and his life depended on the fate of his accomplice who lay dying in the same prison. If his friend confessed, Rohan would be convicted and executed. If not, Rohan might be able to go free. Shortly before his trial Rohan received a note hidden in a bundle of clothing: PVQ RDOWYFQD OW XQSX VQ WSOX FYPVOFC. Should Rohan confess and throw himself on the mercy of the court Or should he stonewall and hope to be let free (The message was actually in French. For those who read French, the ciphertext is MG EULHXCCLGU GHJ YXUJ LM CT ULGC ALJ.) 12. Decrypt the following monoalphabetic cipher. Kahn [page 770] says a similar method was used, albeit in Latin, to record this event. J1629 B1762, 01ug3927 of W45541m B1762, cu71927 of 932 p17483, 48 b1p94820 J16u17y 1, 1645 46 C5219o7, Cumb275160, 26g5160
5.10. EXERCISES 85 13. Ciphers in which pairs of numbers replace each letter are called biliteral or dinome ciphers. A simple way to construct such ciphers is to put the letters of the alphabet into a rectangle and number the rows and the columns. For example, if we use a five-by-five square, and squash i and j together, we have 1 2 3 4 5 1 a b c d e 2 f g h ij k 3 l m n o p 4 q r s t u 5 v w x y z To encipher, replace the letter by its row–column number pair, that is, read from the side first. So box becomes 12 34 53. Deciphering is just translating back into letters. Use the given square to encipher or decipher the following. (a) rectangle. (b) square. (c) 54 66 53 56. (Hint: 41 was added to every number before transmission). (d) 42 32 14 15 23 45 43. The alphabet was entered into the square using the keyword DINOME. (e) Perhaps the first ever use of a password was when Giovanni Argenti, around 1589, used PIETRO and a rectangle with two rows and 10 columns (0 being the first). (The letters jkvwxy did not appear.) Using this method, 17 16 13 13 11 27 13 16 and 24 16 13 13 12 15 gives Argenti’s middle name and his nephew’s name. What are they 14. A larger bipartite cipher was used by Brig. General Leslie R. Groves [Kahn, page 546]. It took the form 1 2 3 4 5 6 7 8 9 0 1 I P I O U O P N 2 W E U T E K L O 3 E U G N B T N S T 4 T A Z M D I O E 5 S V T J E Y H 6 N A O L N S U G O E 7 C B A F R S I R 8 I C W Y R U A M N 9 M V T H P D I X Q 0 L S R E T D E A H E
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Cryptology: An Historical Introduct
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Contents List of Figures 8 1 Caesar
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CONTENTS 5 9 Digraphic Ciphers 167
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List of Figures 1.1 Saint Cyr Slide
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Chapter 1 Caesar Ciphers There are
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11 Examples: Encipher or decipher t
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1.1. SAINT CYR SLIDE 13 paper turne
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1.3. FREQUENCY ANALYSIS 15 PX PBEE
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1.3. FREQUENCY ANALYSIS 17 A bit mo
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1.3. FREQUENCY ANALYSIS 19 Examples
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1.4. LINQUIST’S METHOD 21 the cip
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1.7. EXERCISES 23 12. What is the m
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1.7. EXERCISES 25 (d) VTXLTKBTG LXV
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1.7. EXERCISES 27 (d) IKSUT JKIOT K
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Chapter 2 Cryptologic Terms Cryptog
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Chapter 3 The Introduction of Numbe
Page 33 and 34: 3.1. THE REMAINDER OPERATOR 33 Exam
Page 35 and 36: 3.1. THE REMAINDER OPERATOR 35 Perf
Page 37 and 38: 3.1. THE REMAINDER OPERATOR 37 As a
Page 39 and 40: 3.2. MODULAR ARITHMETIC 39 While %
Page 41 and 42: 3.3. DECIMATION CIPHERS 41 previous
Page 43 and 44: 3.4. DECIPHERING DECIMATION CIPHERS
Page 45 and 46: 3.6. KOBLITZ’S KID-RSA AND PUBLIC
Page 47 and 48: 3.6. KOBLITZ’S KID-RSA AND PUBLIC
Page 49 and 50: 3.9. EXERCISES 49 8. How do we enci
Page 51 and 52: 3.9. EXERCISES 51 (c) Encipher 54 4
Page 53 and 54: 3.9. EXERCISES 53 (b) Encipher secr
Page 55 and 56: Chapter 4 The Euclidean Algorithm I
Page 57 and 58: 4.2. GCD’S AND THE EUCLIDEAN ALGO
Page 59 and 60: 4.3. MULTIPLICATIVE INVERSES 59 (2)
Page 61 and 62: 4.3. MULTIPLICATIVE INVERSES 61 (2)
Page 63 and 64: 4.4. DECIPHERING DECIMATION AND LIN
Page 65 and 66: 4.5. BREAKING DECIMATION AND LINEAR
Page 67 and 68: 4.6. SUMMARY 67 To put it more blun
Page 69 and 70: 4.8. EXERCISES 69 5. Here we work w
Page 71 and 72: Chapter 5 Monoalphabetic Ciphers He
Page 73 and 74: 5.2. KEYWORD MIXED CIPHERS 73 Examp
Page 75 and 76: 5.4. INTERRUPTED KEYWORD CIPHERS 75
Page 77 and 78: 5.6. BASIC LETTER CHARACTERISTICS 7
Page 79 and 80: 5.7. ARISTOCRATS 79 the 69971 or 42
Page 81 and 82: 5.9. TOPICS AND TECHNIQUES 81 5.9 T
Page 83: 5.10. EXERCISES 83 (h) DYVTP KKIQ.
Page 87 and 88: 5.10. EXERCISES 87 17. General Pier
Page 89 and 90: Chapter 6 Decrypting Monoalphabetic
Page 91 and 92: 6.2. DECRYPTING MONOALPHABETIC CIPH
Page 97 and 98: 6.3. SUKHOTIN’S METHOD FOR FINDIN
Page 99 and 100: 6.4. FINAL MONOALPHABETIC TRICKS 99
Page 101 and 102: 6.5. SUMMARY 101 our ciphertext muc
Page 103 and 104: 6.7. EXERCISES 103 Frequency count:
Page 105 and 106: 6.7. EXERCISES 105 53++!305))6*;482
Page 107 and 108: 6.7. EXERCISES 107 93 93 82 48 39 6
Page 109 and 110: Chapter 7 Vigenère Ciphers It was
Page 111 and 112: 7.2. TRITHEMIUS, THE FATHER OF BIBL
Page 113 and 114: 7.3. BELASO, THE UNKNOWN AND PORTA,
Page 115 and 116: 7.4. VIGENÈRE CIPHERS 115 to encip
Page 117 and 118: 7.6. HOW TO BREAK VIGENÈRE CIPHERS
Page 119 and 120: 7.6. HOW TO BREAK VIGENÈRE CIPHERS
Page 121 and 122: 7.7. THE KASISKI TEST 121 Kasiski
Page 123 and 124: 7.8. SUMMARY 123 Repetition Start P
Page 125 and 126: 7.10. EXERCISES 125 2. Little Miss
Page 127 and 128: 7.10. EXERCISES 127 to Gen. E. K. S
Page 129 and 130: 7.10. EXERCISES 129 MEJMY JKXCD LCN
Page 131 and 132: 7.10. EXERCISES 131 22. (a) Use Kas
Page 133 and 134: 7.10. EXERCISES 133 (a) Construct a
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Chapter 8 Polyalphabetic Ciphers Th
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8.1. COINCIDENCES 137 (being born o
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8.2. THE MEASURE OF ROUGHNESS 139 I
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8.2. THE MEASURE OF ROUGHNESS 141 P
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8.3. THE FRIEDMAN TEST 143 The Frie
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8.4. MULTIPLE ENCIPHERINGS 145 Bein
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8.4. MULTIPLE ENCIPHERINGS 147 Just
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8.5. VIGENÈRE’S AUTO KEY CIPHER
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8.5. VIGENÈRE’S AUTO KEY CIPHER
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8.6. PERFECT SECRECY 153 invent now
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8.8. TERMS AND TOPICS 155 multiple
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8.9. EXERCISES 157 6. As is this on
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8.9. EXERCISES 159 13. It has been
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8.9. EXERCISES 161 This is Equation
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8.9. EXERCISES 163 A: AB CDE FGH I
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8.9. EXERCISES 165 26. Decipher SVQ
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Chapter 9 Digraphic Ciphers Althoug
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9.1. POLYGRAPHIC CIPHERS 169 f a g
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9.2. HILL CIPHERS 171 th 2.96 es 1.
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9.2. HILL CIPHERS 173 We will be us
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9.3. RECOGNIZING AND BREAKING POLYG
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9.4. PLAYFAIR 177 Playfair Ciphers:
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9.5. SUMMARY 179 9.5 Summary Polygr
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9.7. EXERCISES 181 (b) The use of
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9.7. EXERCISES 183 10. Just as we c
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9.7. EXERCISES 185 (d) (For those(
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9.7. EXERCISES 187 The rules that W
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Chapter 10 Transposition Ciphers In
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10.3. TURNING GRILLES 191 1 2 3 7 4
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10.4. COLUMNAR TRANSPOSITION 193 co
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10.5. TRANSPOSITION VS. SUBSTITUTIO
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10.6. LETTER CONNECTIONS 197 F 2 G
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10.7. BREAKING THE COLUMNAR TRANSPO
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10.8. DOUBLE TRANSPOSITION 201 Sinc
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10.9. TRANSPOSITION DURING THE CIVI
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10.9. TRANSPOSITION DURING THE CIVI
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10.10. THE BATTLE OF THE CIVIL WAR
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10.13. EXERCISES 209 14. What is a
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10.13. EXERCISES 211 and the second
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10.13. EXERCISES 213 evening Adam h
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10.13. EXERCISES 215 Several codewo
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10.13. EXERCISES 217 4. (which is t
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Chapter 11 Knapsack Ciphers Merkle
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11.3. AN EASY KNAPSACK PROBLEM 221
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11.4. THE KNAPSACK CIPHER SYSTEM 22
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11.4. THE KNAPSACK CIPHER SYSTEM 22
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11.5. PUBLIC KEY CIPHER 227 Even wi
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11.8. EXERCISES 229 2. Given the we
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Chapter 12 RSA Take two large prime
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12.1. FERMAT’S THEOREM 233 Exampl
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12.3. COMPLICATION II: A SUBSTANTIA
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12.3. COMPLICATION II: A SUBSTANTIA
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12.5. COMPLICATION IV: THE LAST ONE
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12.6. PUTTING IT ALL TOGETHER 241 1
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12.8. RSA 243 The RSA Algorithm Set
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12.9. RSA AND PUBLIC KEYS 245 There
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12.10. HOW TO BREAK RSA 247 had to
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12.12. SUMMARY 249 cannot read the
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12.14. EXERCISES 251 6. What is a
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12.14. EXERCISES 253 Bob is going t
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Bibliography [Antonucci] Michael An
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BIBLIOGRAPHY 257 [Shamir] [SRA] A.
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