Introduction to cryptography

Techniques to protect secrets have been around for centuries. The earliest attempts to secure and hide data from adversaries date back to ancient inscriptions discovered on monuments in Egypt, where a special alphabet that was known by only a few trusted people was used. This early form of security is called obscurity and is still used in different forms today. In order for this method to work, it is critical to protect the secret, which would be the secret meaning of the alphabet in the above example. Later in time, finding foolproof ways of protecting important messages was important in both World War One and World War Two. In the late 20^th century, with the introduction of electronics and computers, sophisticated algorithms were developed to secure data, giving rise to a whole new field called cryptography. This chapter discusses the algorithmic aspects of cryptography. One of the uses of these algorithms is to allow secure data exchange between two...