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).