Caesar Cipher can be generalized in such
way that one substitutes wach
letter with another.
This kind of ciphers are called
substitution cipher.
But these kind of ciphers were broken, by
well trained code breakers.
In fact, they use a method called
frequency analysis.
So, they have to find a new cipher
algorithm to keep the security of sending messages.
The breakthrough was achieved by a French
diplomat, Blaise de Vigenere, in
16th. Century.
The algorithm used the Caesar Ciphers
(not only one, but all possible Caesar ciphers).
The significant idea is to change the
Caesar Ciphers according to a key, whichi is given by a sequence of alphabets.
