Cryptology for Non-Mathematicians

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The target audience of these lectures were students of Mathematics and Informatics (Computer Science). However, parts of these notes are accessible for mathematically interested laymen or school children (with a little help from their teachers).

The following sections from Chapter I can be read without mathematicel ambitions: [Sorry, some of the following links point to pages in german. This will change by and by.]

• Cryptology as entertainment
  • Cryptology in novels and stories
  • Cryptology in books for children
  • Cryptology in movies, television, and broadcast
  • Cryptology in art and comics
  • Cryptology in nonfiction
  • Cryptology in puzzles
• Monoalphabetic ciphers
  • ROT 13
  • Monoalphabetic substitution by web form: Encryption and Decryption.
  • Cryptanalysis of the monoalphabetic substitution
  • Statistical analysis of cipher texts
  • Letter frequencies in German, English, Russian and some other languages
  • Bigram frequencies (letter pairs)
  • Frequency count by web form: letter frequencies, bigram frequencies.
  • Example of a statistical cryptanalysis
  • Pattern search
  • Pattern search by web form in a dictionary or in a given text
  • A puzzle from a childrens' magazine
  • Known plaintext attack
  • Some notes on the early history of cryptology
  • Codebooks
• Polyalphabetic ciphers
  • The invention of polyalphabetic encryption
  • Tools for the polyalphabetic substitution
  • Kasiski analysis of a polyalphabetic ciphertext and analysis of the columns
• Cipher devices
  • Cylinder devices
  • History of the cylinder devices
  • The Bazeries cylinder
  • Cryptanalysis of cylinder ciphers
  • Cracking the Bazeries cipher following de Viaris
  • Cylinder ciphers – consequences from the analysis
  • One rotor ciphers
  • Historical rotor machines
  • The Enigma (nonmathematical parts)
• Transposition ciphers
  • Transposition ciphers – examples
  • Cryptanalysis of a column transposition
  • Transposition ciphers – approaches at cryptanalysis

From Chapter II on the stuff – except the introductory remarks of the single sections – needs a higher level of mathematical knowledge.

Remark: How to use cryptology in the real life of today?