# Vigenere Cipher

A Vigenere Cipher is an extended Caesar Cipher where a message is encrypted using various Caesar shifted alphabets.

The following table can be used to encode a message:

## Encryption

For example, encrypting the text `SUPERSECRET`

with `CODE`

would follow this process:

`CODE`

gets padded to the length of`SUPERSECRET`

so the key becomes`CODECODECOD`

- For each letter in
`SUPERSECRET`

we use the table to get the Alphabet to use, in this instance row`C`

and column`S`

- The ciphertext's first letter then becomes
`U`

- We eventually get
`UISITGHGTSW`

## Decryption

- Go to the row of the key, in this case
`C`

- Find the letter of the cipher text in this row, in this case
`U`

- The column is the first letter of the decrypted ciphertext, so we get
`S`

- After repeating this process we get back to
`SUPERSECRET`