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126 CHAPTER 7. VIGENÈRE CIPHERS Headquarters Department of the Tennessee, Near Vicksburg, May 25, 1863. Col. J.C. Kelton, Assistant Adjutant-General, Washington, D.C. COLONEL: Eight men, with 200,000 percussion caps, were arrested whilst attempting to get through our lines into Vicksburg. The inclosed [sic] cipher was found upon them. Having no one with me who has the ingenuity to translate it, I send it to Washington, hoping that some one there may be able to make it out. Should the meaning of this cipher be made out, I request a copy be sent to me. Very respectfully, U.S. Grant, Major-General. The enclosed message was [General Joe] Jackson (miss), May 25, 1863 Lieutenant General Pemberton: My XAFV. USLX was VVUFLSJP by the BRCYAJ. 200000 VEGT. SUAJ. NERP. ZIFM. It will be GFOECSZOD as they NTYMNX. Bragg MJTPHIHZG a QRCM- KBSE. When it DZGJS. I will YOIG. AS. QHY. NITWM do you YTIAM the IIKM. VFVEY. How and where is the JSQMLGUGS- FTVE. HBFY is your ROEEL. J. E. Johnston Decipher the enciphered words. The keyphrase is Manchester Bluff. (Note: there are several errors. Can you fix them) 10. After Vicksburg fell to the Union, soldiers found the following cipher message: Vicksburg, Dec. 26, 1862 Gen J.E. Johnston, Jackson: I prefer O A A V V R. It has reference to X H V K H Q C H F F I B P Z E L R E Q P Z Q N Y K to prevent P N U Z E Y X S W S T P J W at that point. R O E E L P S G H V E L V T Z F I U T L I L A S L T L H I F N O I G T S M M L F G C C A J D J.C. Pemberton Somebody (Pemberton’s clerk) failed to destroy the enciphered message after translating it. Military telegraph clerks in Washington broke the message and recovered the key Manchester Bluff. They were very surprised when they subsequently found that this key worked for many message. Eventually the Confederates, suspecting the cipher was broke, switched to new key. Decipher the message. 11. Captain William Plum [Antonucci] was in charge of Union communications at New Orleans. He received an intercepted message addressed
7.10. EXERCISES 127 to Gen. E. K. Smith, the commander of the Conferederacy’s Trans- Mississippi Department. In the fall of 1964, the southwest campaign was not going well for the Union. Smith’s forces’ next target (north into Missouri Raid the west Advance south to New Orleans Fight to regain a foothold across the Mississippi river) was unknown. Perhaps the cipher gave this target! September 30 To Genl. E. K. Smith: What are you doing to execute the instructions sent you to HCDL- LVW XMWQIG KM GOEI DMWI JN VAS DGUGUHDMITD. If success will be more certain you can substitute EJTFKMPG OPG- EEVT KQFARLF TAG HEEPZZU BBWYPHDN OMOMNQQG. By which you may effect O TPQGEXYK above that part HJ OPG KWMCT patrolled by the ZMGRIK GGIUL CW EWBNDLZL. Jeffn. Davis The last part of the message mentioned patrolling. Perhaps it referred to gunboat patrols on the river, the only patrols likely to interest Confederate high command. So Plum guessed that “that part HG OPB KWMCT patrolled” stood for “that part of the river patrolled”. Plum wrote “this meaning occurred to the author, at first sight, and doubtless would to any one familiar with military affairs in that section.” He then turned to “By which you may effect O TPQGEZYK above that part of the river ...” Perhaps “a crossing” He soon had decrypted the message. Can you (Hint: use Plum’s guesses to help find the keyword.) (So word division led to complete solution. Why leave in word division 15 During the battle of Vicksburg Grant drove between the forces of Permberton and Joe Johnston, forcing Johnston into the city, which Grant then besieged. Johnston telegraphed for reinforcements. Unfortunately, the cipherer made mistakes, and the telegrapher added his own (confusing R (− −−) with S (− − −), and I (− −) with a pair of E’s (−)). After Kirby Smith spent 12 fruitless hours trying to read this message, he finally sent his chief of staff, Major Cunningham, on horseback around the flank of the Union armies to retrieve the message directly. By the time Cunningham reached Johnston, Johnston’s army was completely cut off from Smith. After this, the Confederates retained word division [Pratt 186–7]. This is not to imply that the North was cryptologically far more advanced than the South. General Albert Myer, in his A Manual of Signals: for the use of Signal Officers in the Field, he seemed to imply that in Vigenèretype systems the keys should be chosen at will by the sender and sent at the start of the transmission! That is, send both the key and ciphertext! 15 “In 1862 South adopted the centuries-old Vigen’ere as its principal official cipher, the proceeded to violate its inherent strengths for the time by such practices as retaining plaintext word length, interspersing plain text and cipher, etc” Ralph E. Weber, [Weber]
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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
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3.1. THE REMAINDER OPERATOR 33 Exam
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3.1. THE REMAINDER OPERATOR 35 Perf
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3.1. THE REMAINDER OPERATOR 37 As a
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3.2. MODULAR ARITHMETIC 39 While %
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3.3. DECIMATION CIPHERS 41 previous
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3.4. DECIPHERING DECIMATION CIPHERS
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3.6. KOBLITZ’S KID-RSA AND PUBLIC
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3.6. KOBLITZ’S KID-RSA AND PUBLIC
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3.9. EXERCISES 49 8. How do we enci
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3.9. EXERCISES 51 (c) Encipher 54 4
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3.9. EXERCISES 53 (b) Encipher secr
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Chapter 4 The Euclidean Algorithm I
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4.2. GCD’S AND THE EUCLIDEAN ALGO
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4.3. MULTIPLICATIVE INVERSES 59 (2)
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4.3. MULTIPLICATIVE INVERSES 61 (2)
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4.4. DECIPHERING DECIMATION AND LIN
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4.5. BREAKING DECIMATION AND LINEAR
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4.6. SUMMARY 67 To put it more blun
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4.8. EXERCISES 69 5. Here we work w
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Chapter 5 Monoalphabetic Ciphers He
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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 and 84: 5.10. EXERCISES 83 (h) DYVTP KKIQ.
Page 85 and 86: 5.10. EXERCISES 85 13. Ciphers in w
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: 7.10. EXERCISES 125 2. Little Miss
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
Page 135 and 136: Chapter 8 Polyalphabetic Ciphers Th
Page 137 and 138: 8.1. COINCIDENCES 137 (being born o
Page 139 and 140: 8.2. THE MEASURE OF ROUGHNESS 139 I
Page 141 and 142: 8.2. THE MEASURE OF ROUGHNESS 141 P
Page 143 and 144: 8.3. THE FRIEDMAN TEST 143 The Frie
Page 145 and 146: 8.4. MULTIPLE ENCIPHERINGS 145 Bein
Page 147 and 148: 8.4. MULTIPLE ENCIPHERINGS 147 Just
Page 149 and 150: 8.5. VIGENÈRE’S AUTO KEY CIPHER
Page 151 and 152: 8.5. VIGENÈRE’S AUTO KEY CIPHER
Page 153 and 154: 8.6. PERFECT SECRECY 153 invent now
Page 155 and 156: 8.8. TERMS AND TOPICS 155 multiple
Page 157 and 158: 8.9. EXERCISES 157 6. As is this on
Page 159 and 160: 8.9. EXERCISES 159 13. It has been
Page 161 and 162: 8.9. EXERCISES 161 This is Equation
Page 163 and 164: 8.9. EXERCISES 163 A: AB CDE FGH I
Page 165 and 166: 8.9. EXERCISES 165 26. Decipher SVQ
Page 167 and 168: Chapter 9 Digraphic Ciphers Althoug
Page 169 and 170: 9.1. POLYGRAPHIC CIPHERS 169 f a g
Page 171 and 172: 9.2. HILL CIPHERS 171 th 2.96 es 1.
Page 173 and 174: 9.2. HILL CIPHERS 173 We will be us
Page 175 and 176: 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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