Editing Autokey cipher (section)

==History==
This cipher was invented in 1586 by [[Blaise de Vigenère]] with a reciprocal table of ten alphabets. Vigenère's version used an agreed-upon letter of the alphabet as a primer, making the key by writing down that letter and then the rest of the message.<ref>{{Cite web|url=http://crypto.interactive-maths.com/vigenegravere-cipher.html|title=Vigenère Cipher|website=Crypto Corner|language=en|access-date=2018-08-13}}</ref>

More popular autokeys use a [[tabula recta]], a square with 26 copies of the alphabet, the first line starting with 'A', the next line starting with 'B' etc. Instead of a single letter, a short agreed-upon keyword is used, and the key is generated by writing down the primer and then the rest of the message, as in Vigenère's version. To encrypt a plaintext, the row with the first letter of the message and the column with the first letter of the key are located. The letter in which the row and the column cross is the ciphertext letter.