Cryptography study notes (2): Some ancient encryption algorithms

Substitution cipher

  • A key for a substitution cipher is a subsitution that basiclly says how to map our letters.

Caesar cipher

  • Actually is not really a cipher at all. And the reason is that it doesn’t have a key.
  • Basiclly is a substitution cipher where the substitution is fixed. Namely, it’s a shift by three.

Vigener cipher (16’th centry, Rome)

  • Key is a word.

Rotor Machines

  • The Hibber machine (single rotor).
  • The Enigma machine (3 - 5 rotor).