Electrical and Mechanical Cipher Machines

Using machinery to automate encryption permitted ciphers to be much more complicated than those which can reasonably be applied by hand without too many mistakes. And this was true even though machines had to be reliable and inexpensive, and this meant they could only carry out fairly simple operations. (Today, of course, the microchip has changed everything immensely!)

There are several types of cipher machine that we will examine in this section; and a few more that belong to another section, since they hint at the computer age to follow.

• Early Machine Ciphers
  • The Bazeries Cylinder
  • The Kryha Cryptograph
  • The Hill Cipher
  • The RED Machine
  • The Reihenscheiber
  • The A-22 Cryptograph
• The Hagelin lug and pin machines
  • Cryptanalysis of the Basic Lug and Pin Machine
• Rotor Machines - and their PURPLE cousins
  • Rotor Machine Basics
  • The Interval Method
  • The Method of Isomorphs
  • PURPLE, CORAL, and JADE
• The Enigma: a unique rotor machine
  • Basic Principles of the Enigma
  • The Uhr Box
  • The Enigma A and Enigma B
  • Relatives of the Enigma
  • Cryptanalysis of the Enigma
    • Cliques on the Rods
    • Indicators and Jefferys Sheets
    • The Bombe and the Diagonal Board
• An American Achievement: the ultimate rotor machine
• Miscellaneous Machine Ciphers
  • The Hagelin B-211
  • Sweden's HC-9
  • LACIDA
• Conclusions for Chapter II
  • Fantastic Rotor Machines
  • Child's Play
  • Irregular Rotor Movement

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