Vigenere Cipher Explanation

You will learn how the Vigenere Cipher works.

How it works

The Vigenère cipher is a more complex version of shift cipher. It uses two things to encode plaintext: a keyword, and a Vigenère square, like the one on the left. It takes 26 alphabets, each one moving one to the left. To encode, you take a keyword and repeat it until it is matching in length with the plaintext. Assuming that letters A-Z are numbers 0-25, the code Ci for each plain text letter Pi with the corresponding keyword letter Ki is simply Ci = (Pi+Ki) mod 26.