Autokey Cipher
The Autokey Cipher is a polyalphabetic substitution cipher. It is closely related to the Vigenère Cipher, but uses a different method of generating the key. It was invented by Blaise de Vigenère in 1586, and is in general more secure than the Vigenère Cipher.

The following buttons can be used to manipulate the text into various forms such as uppercase, lowercase, reverse text, etc. The choice text chosen will be copied and a new page will be opened.

The Autokey cipher uses the following tableau (the 'tabula recta') to encipher the plaintext: