Introducing classical cryptography techniques

From the earliest algorithms that are easily hackable to the recent ones that rely on hard-to-solve mathematical problems, cryptographic techniques have evolved over the decades to become stronger against attacks.

In this section, we will look at how cryptography works in classical computation. This will serve as an introduction to quantum cryptography in the next section.

Let's begin by introducing the basics and the vocabulary of classical cryptography.

The basics of cryptography

First things first, what is cryptography and why is it needed? Suppose you want to send a secret message to someone. If you do not possess a secure communication channel with this person, whether physical or virtual, then whatever means of communication you use, your message has a chance of being intercepted by a third party. This third party, also called an adversary, eavesdropper, or Eve, may take various forms and interfere at any point of...