The need to create secure codes is said to go back to Julius Caesar, who moved letters in his messages up by three through the alphabet. That is encoding. How would you decode such a message?
Modern day cryptography, which is the art of coding and decoding messages, has taken on a new relevance with computer transfer of information, and it retains its traditional relevance in military settings. It makes use of a public key, which does not require its users to share a key as this would, make their coded message susceptible to attack.
Traditional number theory has produced a number of means of securely coding messages, but “securely” is a relative term. Modern methods depend on the simple ability to multiply two large numbers together and the very difficult problem of finding those factors given only their product. Continue reading