Sur quelques usages de la cryptographie à la Renaissance

Résumé 0

Cryptography, i.e. the science of secret writing, has a very long history, and each of us knows that most of the peoples of Antiquity have used what we call cipher, that is to say a secret code known only from initiated people, who are the only ones able to decipher it in order to make clear the true meaning. This code is protected, with more or less subtlety, from all kinds of indiscretion. From the XIVth century, the Administration of most Italian States, just as the Roman Curia, have had their own cipher office. In the XVth century, the architect, philosopher and writer Alberti built a substitution engine for the use of ambassadors and other missionaries. But it is above all the German abbot Johann Trithemius, at the end of the XVth century and the beginning of the XVIth (see his Steganographia and his Polygraphia) and, at the end of this same century, the Frenchman Biaise de Vigenère (see his Traité des chiffres ou secrètes manières d’écrire) who perfected some precise methods of cryptography. Although these methods fail to build up a universal language, they can be regarded as a thorough research of the means which allow the passage from one language (natural or artificial) to another. With the “steganamorphic” reading of Beroalde de Verville, one can discover a shifting of the eye and mind in order to decipher under (or beside it) the text, a second text, a sort of hypertext, which contains the essential truth of the message which must be hidden to the common people.