Activity 3: Overview

Last week you learned about some of the history of cryptography and how to encrypt and decrypt messages using some of the oldest cryptographic techniques. Whilst these techniques are interesting and show us how cryptography works, they are not secure enough for modern day use. In this week you will learn about some modern day cryptography techniques and how they are used to secure communication on the internet.

To do this we first have to understand the difference between private key and public key cryptography. In this activity you will learn about private and public key cryptography.

Learning objectives

By the end of this activity, you should be able to:

• explain the concepts of private key and public key cryptography
• Apply modern ciphers to encrypt and decrypt messages.