Article overview of encryption methods from simple ciphers to block ciphers. Covers Caesar cipher, Vigenère cipher, and introduces DES (Data Encryption Standard) created by IBM in the 1970s for protecting financial transactions and bank cards.
Researchers used simulated annealing to decrypt a 500-year-old cipher from a 1542 letter sent by Cardinal Alessandro Farnese to the papal nuncio Giovanni Poggio. The letter, stored in the Vatican Archives, contained a polyalphabetic substitution cipher that had remained unsolved until computational methods were applied to recover the key and plaintext.