Some other interesting examples of codes (cryptography) from history and modern times that could be explored with a class include Alberti’s disk, Vigenère cipher (image included), Playfair cipher and the use of a Scytale. A modern form of cryptography used within ICT that could explored includes Steganography. This is the process of hiding a file, message or image within another file or image. A simple example of Steganography is the use of QR codes.