Codes and ciphers : Julius Caesar, the Enigma, and the internet R.F. Churchhouse

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Bibliografie si index la sfarsitul cartii

Machine generated contents note: 1 Introduction 1 -- Some aspects of secure communication I -- Julius Caesar's cipher 2 -- Some basic definitions 3 -- Three stages to decryption identification, breaking and setting 4 -- Codes and ciphers 5 -- Assessing the strength ofa ciphersystem 7 -- Error detecting and correcting codes 8 -- Other methods of concealing messages 9 -- Ivlodulararithmetic 10 -- Modular addition and subtraction ofletters 11 -- Gender 11 -- End matter 12 -- Z FromJuliusCaesar tosimplesubstitution 13 -- Julius Caesarciphers and theirsolution 13 -- Simplesubstitutionciphers 15 -- How to solve a simple substitution cipher 17 -- Letter frequencies in languages other thanEnglish 24 -- How many letters are needed to solve a simple substitution cipher? 26 -- 3 Polyalphabeticsystems 28 -- StrengtheningJulius Caesar Vigentre ciphers 28 -- HowtosolveaVigenirecipher 30 -- Indicators 33 -- Depths 34 -- Recognising'depths' 34 -- How much text do we need to solveaVigenere cpher? 37 -- Jefferson's cylinder 37 -- 4 Jigsaw ciphers 40 -- Transpositions 40 -- Simple transposition 40 -- Doubletransposition 44 -- Other forms oftransposition 48 -- Assessment of the security of transposition ciphers 51 -- Double encipherment in general 52 -- 5 Two-letterciphers 54 -- Monograph to digraph 54 -- MDTM ciphers 56 -- Digraph to digraph 58 -- Playfair encipherment 59 -- Playfair decipherment 60 -- Cryptanaytic aspects of Playfair 61 -- DoublePlayfair 61 -- 6 Codes 64 -- Characteristics of codes 64 -- Onepartand to-part codes 65 -- Codeplusadditive 67 -- 7 Ciphersforspies 72 -- Stencil ciphers 73 -- Book ciphers 75 -- Letter frequencies in book ciphers 79 -- Solving a book cipher 79 -- Indicators 86 -- Disastrous errors in using a book cipher 86 -- 'GAito"sd phers 88 -- One-time pad 92 -- 8 Produciingrandomnumbersandletters 94 -- Random sequences 94 -- Producing random sequences 95 -- Coin spinning 95 -- Throwingdice 96 -- Lotterytype draws 97 -- Cosmic rays 97 -- Amplifier noise 97 -- Pseudo-random sequences 98 -- Linear recurrences 99 -- Using a binary stream ofkey for endpherment 100 -- Binarylinarsequences as key generators 101 -- Cryptanalysisofa linear recurrence 104 -- Improving the security of biary keys 104 -- Pseudo-randomnumbergenerators 106 -- The mid-square method 106 -- Linearcongruential generators 107 -- 9 TheEnigmaciphermachine 110 -- Historicalbackground 110 -- TheoriginalEnigma 112 -- Encipherment using wired wheels 116 -- EnciphermentbytheEnigma 118 -- The Enigmaplugboard 121 -- TheAchilles heelof the Enigma 121 -- The indicator 'chains' in the Enigma 125 -- Aligningthe chains 128 -- Identifying RI and its setting 128 -- Doublyenciphered Enigma messages 132 -- TheAbwehr Enigma 132 -- 10 TheHagelinciphermachine 133 -- Historical background 133 -- Structureofthellagelinmachine 134 -- Enciphermentonthe Hagelin 135 -- Choosing the cage for the Hagelin 138 -- The theoretical 'work factofo' fortheHagein 142 -- Solving the Hagelin from a stretch of ke 143 -- Additional featursof rheHagelin machine 147 -- Theslide 147 -- Idenrifying the slide in a cipher message 148 -- Overlapping 148 -- solving the Hagelin from cipher texts only 150 -- 11 BeyondtheEnigmia 153 -- TheSZ42: a pre-electronic machine 153 -- Description of the 742 machine 155 -- EnciphermentontheSZ42 t55 -- Breakingandsettingthe5Z42 158 -- Modifications tothe SZ42 159 -- 12 Publickeycryptography 161 -- Historicalbackground 161 -- Securityissues 163 -- Protection ofprogramsand data 163 -- Encipherment of programs, dataand messages 164 -- The key distribution problem 166 -- The Difie-Hellman key exchange system 166 -- Strength of the Diffie-Hellman system 168 -- 13 Encipherment and the internet 170 -- Generalisation of simple substitution 170 -- Factorisation of large integers 171 -- The standard method of factorisation 172 -- Fermat's'itde Theorem' 174 -- The Fermat-Euler Theorem (as needed in theRSA sstem) 175 -- Enciphermen and decipherment keys in the RSA system 175 -- The encipherment and decipherment processes in the RSA sysem 178 -- How does the key-owner reply tocorrespondents? 182 -- The Data Encryption Standard (DES) 183 -- Security of te DES 184 -- Chaining 186 -- Implementation of the DES 186 -- Using both RSA and DES 186 -- A salutary note 187 -- Beyond dteDES 187 -- Authentication and signature verification 188 -- Ellipticcurvecryptography 189 -- Appendix 190 -- Solutions to problems 218 -- References 230 -- Name index 235 -- Subject index 237.