GoKawiilResearchers use simulated annealing to break Farnese's 1542 papal cipher
A 1542 ciphered letter sent from Cardinal Alessandro Farnese in Rome to nuncio Giovanni Poggio at Charles V's court has been decrypted using a simulated-annealing algorithm. The eight-page document, held in the Vatican Apostolic Archive, mixed plain Italian text with number sequences that could be read multiple valid ways, making manual decoding extremely difficult. Researchers matched the recovered key to a related cipher table catalogued by scholar Aloys Meister in 1906, confirming the connection to papal secretary Giovanni Ricci da Montepulciano.