iGCSE Computer Science - Distance Learning

Tutor Marked Assignment 6
Tutor Marked Assignment 8 (Programming)

Methods of Encryption

Different types of encryption technique are used to protect our data and each of these varies in terms of how complex the encryption needs to be. In the GCSE you will be expected to understand the difference between the Caesar Cipher which is a form of shift cipher and more complex examples such as a substitution cipher where letters are replaced with random other letters (this is sometimes also called a nomenclator).

The video lesson below is taken from our A Level masterclasses, but covers a range of encryption techniques and their uses. The two ciphers that you should be aware of in this video are the Caesar Cipher and the Substitution Cipher.

One of the most secure forms of encryption which is used by SSL is asymmetric encryption where a public key and a private key are both used with one encrypting and the other decrypting.

Asymmetric Encryption

It’s important to be aware that you do not need to be able to write the code for any of these methods of encryption , but she should be able to compare different methods and identify which one is more secure (a useful rule of thumb here, is that the Caesar cipher is never that secure!).