] Le chiffrement dans l'histoire. De 4 000 ans à nos jours,
] du Carré de Vignére à la PGP

Translation: Cryptography in history, from 4000 years ago until today, from Vigenere's square to PGP.

Even though it's in French, I'm linking to this site because they have a nice example of an "auto-key" table, which is another system created by Vigenere (and may help with cracking Kryptos...)

Vigenere Auto-Key System (in French)