Adjective
autokey (not comparable)
(cryptography) Being a cipher that incorporates the plaintext into the key.
During the Crimean War of the 1850s, Babbage broke Vigenère's autokey cipher as well as the much weaker cipher that is called Vigenère cipher today. citation His discovery was kept a military secret, and was not published. Source: Internet
Such schemes are known as self-synchronizing stream ciphers, asynchronous stream ciphers or ciphertext autokey (CTAK). Source: Internet