How to Encode and Decode Using the Vigènere Cipher

Khan Academy

SOLVED:The autokey cipher is similar to the Vigenère cipher, except that rather than repeating the key, it simply uses the key to encrypt the first few letters and then uses the plaintext itself (shifted over) to continue the encryption. For example, in order to encrypt the message "The autokey cipher is cool" using the keyword random, we proceed as follows: Plaintext t h i a u t ∘ k e y c i P h e I i s c 0 0

Tutorial: Caesar and Vigenere Ciphers | CodeHS

Vigenere Verschlüsselung: Erklärung und Entschlüsseln