By Elisa Bertacin Faced with the “challenge of transmitting messages or communications accessible to the limited few, “Cryptography” has proven to be a concept that has always fascinated man. Cryptography is that science which aims to provide an instrument capable of keeping secret all information that is not for public disclosure. The operation with which information is hidden is referred to as encryption. To encrypt information, an algorithm (cipher) is used. The message that is to be encrypted is referred to as plaintext, which, through the use of a key, is converted into the encrypted text or the ciphertext. Decryption, on the other hand, is the reverse process for which a ciphertext is converted into plaintext through the use of the key to the encryption. Throughout history, encryption methods have prevalently been used by four categories of people: the military, diplomats, diarists, and lovers. Given the context provided by the paper, it is obvious that the first two are what interest us the most, and in particular the military. In his time, Plutarch spoke of the Spartan generals, who sent and received coded messages using the scytale, a small cylinder of wood. The message was written on a thin strip
