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26 CHAPTER 1. CAESAR CIPHERS 16. The Confederate Army used several rather insecure cipher systems during the Civil War [Gaddy]. For example, “To Gen. Beauregard, 11 March 1862: Sir: Your dispatch just received. The day of the month on which it is written will indicate the letter of the alphabet corresponding with A. Yesterday 10th J-A. I repeat it that we may know if the operator conveyed it correctly. EFNTI FJJZE XIZMV IIVRI FEJRK LIURP NYVIV TREKY VK- IFF GJAFZ EPFLN ZKYLK DFJKV WWVTK On the 27th of the month “A” will correspond to “C”. Gen. Albert Sidney Johnston (Decataur)” (a) Use frequency analysis to find the key and decrypt the message. (b) What date was it sent on 17. Some years after the Civil War, Joseph Willard Brown described the following incident [Brown, pages 210–2]. “One [message] from Gen. Beauregard just after the battle of Shiloh, (6-7 April 1862) giving the number and condition of his forces at Corinth, was formed by merely putting the last half of the alphabet first, that is, substituting M for A, N for B, O for C, etc. This dispatch fell into our hands and first reached Richmond in a northern newspaper.” Perhaps this quote refers to a long (5000-ish) word report of Beauregard’s sent on April 11th. Here is different, brief report of Beauregard’s, written during the battle, that has been enciphered via this method. Please decipher it. IQFTU EYADZ UZSMF FMOWQ PFTQQ ZQYKU ZEFDA ZSBAE UFUAZ UZRDA ZFARB UFFEN GDSMZ PMRFQ DMEQH QDQNM FFXQA RFQZT AGDEF TMZWE NQFAF TQMXY USTFK SMUZQ PMOAY BXQFQ HUOFA DKPDU HUZSF TQQZQ YKRDA YQHQD KBAEU FUAZX AEEAZ NAFTE UPQET QMHKU ZOXGP UZSAG DOAYY MZPQD UZOTU QRSQZ QDMXM EVATZ EFAZI TARQX XSMXX MZFXK XQMPU ZSTUE FDAAB EUZFA FTQFT UOWQE FARFT QRUST F 18. Here are quotes in French. Use frequency analysis to decrypt them. (a) FU ALUHXYOL XY FBIGGY YMN ALUHXY YH WY KOCF MY WIHHUBUNCN GCMYLUVFY OH ULVLY HY MY WIHHUCN JUM GCMYLUVFY. (b) DXOLH XGHPH SODLQ GUHGH FHTXH ODURV HDGHV HSLQH VMHPH IHOLF LWHGH FHTXH OHSLQ HHVWV XUPRQ WHHGH URVHV HWGHF HTXLH OHEXL VVRQS RUWHG HIOHX UV. (c) VY AL N CNF ZBVAF QVAIRAGVBAF N OVRA NCCYVDHRE HAR CRAFRR DHR YBA GEBHIR QNAF HA YVIER DHN UNGRGER YR CERZVRE NHGRHE QR PRGGR CRAFRR.
1.7. EXERCISES 27 (d) IKSUT JKIOT KYZWA ATKUK ABXKI USOWA KUAIN GIATL GOZYK YXNGZ URKYJ OLLKX KTZYR GYAXR GYIKT KKTNG HOZJX GSGZO WAKHX ORRKT ZVXKR GZYSO TOYZX KYIUT WAKXG TZYVU AXTUA YBORV KAVRK GYYOY GADJK XTOKX YXGTM YZXUA VKLAZ ORKKZ JKYMX GTJYX KHAZK KVGXT UAYJK THGYR GVOKI KKYZK IUAZK K. 19. Here are several quotes in German. Use frequency analysis to decrypt them. (a) LQM XWTQBQS QAB SMQVM EQAAMVAKPINB EQM DQMTM LMZ PMZZMV XZW- NMAAWZMV AQKP MQVJQTLMV AWVLMZV MQVM SCVAB. (b) XL BLM UXLLXK WTL ZXKBGZLMX WBGZ OHG WXK PXEMD TEL XBGX ATEUX LMNGWX YNK ZXKBGZ ATEMXG. (c) YCQBJ UHLUH IJUXJ CQDRU IIUHT YUKDW BKSAI VQBBU PKLUH XKJUD YDTUH ZKDWU DTIYU PKUHJ HQWUD. 20. Here are several quotes in Italian. Use frequency analysis to decrypt them. (a) LQR JLLNLJCX MJUU JVKRIRXWN BR LXWMDLN RW UDXPX MXEN WXW YDX YRD JUCX BJURA N YXR LXW VJBBRVX MJWWX MR LJMNAN WNLNBBRCJCX. (b) XTDPCL WL GZWRLCP P NTPNL RPYEP NSP AZY BFT DFP DAPCLYKP TY NZDP ELWT NSP W EPXAZ WP YP AZCEL DT CPAPYEP. (c) ES TWSLJAUW KA TWDDS W JAVWFLW EA KA EGKLJG UZW LJS IMWDDW NWVMLW KA NMGD DSKUASJ UZW FGF KWYMAJ DS EWFLW. 21. What is the question that goes along with this quote Think frequency analysis. Upon this basis I am going to show you how a bunch of bright young folks did find a champion; a man with boys and girls of his own; a man of so dominating and happy individuality that Youth is drawn to him as is a fly to a sugar bowl. It is a story about a small town. It is not a gossipy yarn; nor is it a dry, monotonous account, full of such customary “fill-ins” as “romantic moonlight casting murky shadows down a long, winding country road.” Nor will it say anything about twinklings lulling distant folds; robins carolling at twilight, nor any “warm glow of lamplight” from a distant cabin window. No. It is an account of up-and-doing activity; a vivid portrayal of Youth as it is today; and a practical discarding of that worn-out notion that “a child don’t know anything.” 22. Use frequency analysis to decrypt the following Caesar ciphers. They are a bit trickier. (a) W LWNWCNWLD SEPD JK AO EO ZEBBEYQHP PK YKJOPNQYP WJZ YKJBQOEJC PK YNULPWJWHUV (b) BLABX LOMZF DKFTL FDUOW ARDLB XMOUZ SMHLD KBABG XMDXL FFLDI UFTAZ LFTMF UEZAF ZLMDX KMEBA BGXMD NGFMO MDLRG XRDLC GLZOK MZMXK EUEOM ZEFUX XPLOA PLFTL YLEEM SL
Page 1 and 2: Cryptology: An Historical Introduct
Page 3 and 4: Contents List of Figures 8 1 Caesar
Page 5 and 6: CONTENTS 5 9 Digraphic Ciphers 167
Page 7 and 8: List of Figures 1.1 Saint Cyr Slide
Page 9 and 10: Chapter 1 Caesar Ciphers There are
Page 11 and 12: 11 Examples: Encipher or decipher t
Page 13 and 14: 1.1. SAINT CYR SLIDE 13 paper turne
Page 15 and 16: 1.3. FREQUENCY ANALYSIS 15 PX PBEE
Page 17 and 18: 1.3. FREQUENCY ANALYSIS 17 A bit mo
Page 19 and 20: 1.3. FREQUENCY ANALYSIS 19 Examples
Page 21 and 22: 1.4. LINQUIST’S METHOD 21 the cip
Page 23 and 24: 1.7. EXERCISES 23 12. What is the m
Page 25: 1.7. EXERCISES 25 (d) VTXLTKBTG LXV
Page 29 and 30: Chapter 2 Cryptologic Terms Cryptog
Page 31 and 32: 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
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5.6. BASIC LETTER CHARACTERISTICS 7
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5.7. ARISTOCRATS 79 the 69971 or 42
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5.9. TOPICS AND TECHNIQUES 81 5.9 T
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5.10. EXERCISES 83 (h) DYVTP KKIQ.
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5.10. EXERCISES 85 13. Ciphers in w
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5.10. EXERCISES 87 17. General Pier
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Chapter 6 Decrypting Monoalphabetic
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6.2. DECRYPTING MONOALPHABETIC CIPH
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6.3. SUKHOTIN’S METHOD FOR FINDIN
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6.4. FINAL MONOALPHABETIC TRICKS 99
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6.5. SUMMARY 101 our ciphertext muc
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6.7. EXERCISES 103 Frequency count:
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6.7. EXERCISES 105 53++!305))6*;482
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6.7. EXERCISES 107 93 93 82 48 39 6
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Chapter 7 Vigenère Ciphers It was
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7.2. TRITHEMIUS, THE FATHER OF BIBL
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7.3. BELASO, THE UNKNOWN AND PORTA,
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7.4. VIGENÈRE CIPHERS 115 to encip
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7.6. HOW TO BREAK VIGENÈRE CIPHERS
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7.6. HOW TO BREAK VIGENÈRE CIPHERS
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7.7. THE KASISKI TEST 121 Kasiski
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7.8. SUMMARY 123 Repetition Start P
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7.10. EXERCISES 125 2. Little Miss
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7.10. EXERCISES 127 to Gen. E. K. S
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7.10. EXERCISES 129 MEJMY JKXCD LCN
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7.10. EXERCISES 131 22. (a) Use Kas
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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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