Genoa. Birth of Leon Battista Alberti, one of the leading figures of the Renaissance: painter, composer, poet, philosopher, and author of a treatise on flies and an oratory at his dog’s funeral. Alberti also proposed a simple but highly effective trick in information encryption: switching between two or more encryption alphabets to confuse decryption. This was the first significant advance in encryption in over a thousand years, during which decryption had always held the upper hand. Alberti, however, did not fully develop the concept, which would be developed later by Johannes Tothemius, then Giovanni Porta, and finally Blaise de Vignere, whose name the final form would be called: Vignere Cypher. He uses as many as 26 different encryption alphabets, each shifted by one letter from the previous one, making the system impervious to letter-frequency analysis, the weakness of previous ciphers. His work culminates in his Traicté de Chiffres of 1586. Ironically, this is the same year that Thomas Phelippes cracked the secret code in Mary Queen of Scots’ letters. If Mary had read the treatise and used the Vigneré Cypher, Phelippes would not have been able to crack her code, and Mary would not have been beheaded. In any case, the Vigneré Cypher would remain largely unknown for another two centuries.
