# 1. Introduction

**Encryption** is the process of scrambling data in such a way that only legitimate users can read it.

This is what *plaintext* i.e. unencrypted data looks like

**Humpty Dumpty sat on a wall.**

and this is what *ciphertext *i.e. the encrypted version might look like

**jkd2f*hkdfh7$171kjfh7d1h4d**

Encryption works by scrambling the original data using an *encryption algorithm.*

The encryption algorithm is a set of mathematical steps applied to the original text to change it into cyphertext. Each standard algorithm has a name, such as the AES-256 algorithm.

The algorithm uses a very large digital number (key) to do the conversion. It is extremely difficult for a normal computer to work out what is the correct key in a reasonable amount of time.

Encryption can also be applied to 'real-time' streaming data for copy protection purposes.

For example only paid-up subscribers are able to access encrypted commercial entertainment streams or satellite broadcast channels.

This section will describe two types of technologies

- Symmetric key encryption
- Assymetric key encryption