The other method is called a substitution cipher. For instance, the rail fence cipher is one of many examples of transposition and alternates the letters of a message in a zigzag pattern that moves between two consecutive rows. Transposition involves rearranging letters in a word or sentence to make them unreadable. The result was cryptography, a field that developed two distinct branches: transposition and substitution. At that time, Greece was threatened by Persia and realized that secure communication was essential. While cryptography might seem like a modern phenomenon, it actually dates back to the fifth century BC.

Big Idea #1: Secret codes developed early on in human history and evolved quickly. You will also find out how a weak code had an impact on Mary, Queen of Scots and why your government wants to keep you from using the next state-of-the art encryption method. In this article, you will learn how to encrypt your private letters so that only the intended recipient can read them. The article also talks about technological advances in cryptography and code breaking. We’ll learn about how those codes were broken by spies and other people who wanted access to them. It begins with ancient times, when people used codes to send messages. This article will talk about how cryptography and code breaking have evolved over the years. It was instrumental in determining the outcome of wars and whether someone would live or die. Cryptography has been used in many historical ruses and schemes. When you were a kid, did you ever create your own secret code to exchange messages with your friends? Humans have been fascinated by cryptic communication for thousands of years.

The code book by simon singh