Teach Computing

Revision notes, activities, lesson plans, teaching ideas, and other resources for GCSE, A-Level, and IB Computer Science teachers and students.

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Examples of Local Cryptocurrencies

Digital Money for Local Communities covers three examples of country-wide c...

Hash function A hash function takes arbitrary sized input data (e.g. a fil...

Cryptocurrencies vs regular currencies

What is Bitcoin and How Does it Work? is a high level overview of the Bitco...

Examples of Cryptocurrencies

Bitcoin is by far the most well known cryptocurrency. The Bitcoin website w...

Practice paper 3 exam questions

One of the drawbacks of the yearly case study is that there are no past p...

Emergency Management System Explainer Video

This short video gives an overview of some EMIS features. It includes many ...

Geographic Information Systems (GIS)

For some functionality, an EMIS may also be connected to a GIS (Geographic ...

Programming languages - from Scratch to machine code

The CS Field Guide has a very comprehensive guide to different types of pro...

Assembly language simulators

There are several assembly language simulators available for use online. Si...

Resources discount offer

1.4 Security

This topic in the IGCSE syllabus is split into four clear sections which deal with the risks to data posed by accidental or malicious actions, the methods that can be used to keep data safe, and the protection of online systems. There is also a requirement for students to apply this knowledge to real-life scenarios. For the 2016 examination session Cambridge have also added Secure Socket Layer (SSL) and Transport Layer Security (TLS) to the syllabus. Click here for recommended Cambridge IGCSE Computer Science textbooks.

1.4.1 The need to keep data safe from accidental and malicious damage

Data security

Examples of database security problems

The news articles below cover some of the major risks of malicious actions such as hacking or malware. Myriad examples of these problems exist (and new ones seem to appear every few weeks), but the examples below highlight some of the more famous cases (and the greatest losses).

Updated: 2015-04-18

1.4.2 Keeping data safe during storage and transmission

Password security

Secure passwords

CommonCraft popularised the paper-and-marker pen style of video explanation, and some of their original videos are still the best. Secure Passwords Explained by CommonCraft does exactly as you might expect.

Microsoft's Password Checker and the site How Secure is my Password? offer quick ways to see how the complexity of a password significantly alters how easy it is to crack: for obvious reasons it is probably better to use these sites with imaginary passwords rather than your real passwords!

Updated: 2015-04-10
Encryption techniques

Encryption (National Codes Centre)

The National Codes Centre at Bletchley Park (who know a thing or two about ciphers) have comprehensive lesson plans, teacher's notes, and student activities for various types of encryption, from simple substitution ciphers (Caesar ciphers) through the infamous Enigma and Lorenz ciphers to modern day methods.

Updated: 2015-04-16


Very detailed but clear explanations of the various types of encryption systems, from simple substitution ciphers (Caesar ciphers) to modern public key encryption systems. The page also explains the types of attacks that can be performed against ciphers, such as known plaintext attacks and frequency analysis attacks. A variety of interactive applets held improve understanding.

Updated: 2015-04-19
Encryption systems

Braingle: Codes, Ciphers, Encryption and Cryptography

Braingle contains extensive notes on many different types of cipher systems from Caesar ciphers to four-square ciphers. There are dozens of examples and some interactives to help students understand the different ways plaintext can be encrypted. This could be a good site to support a lesson starter activity or extension activities for more advanced students who are interested in encryption systems.

Updated: 2015-04-25
Caesar cipher

Caesar cipher

A simple interactive that implements a basic Caesar cipher. One great use for this is to highlight just how weak Caesar ciphers are. By giving students examples of ciphertext and asking them to use this tool to break them, they should realise just how easy it is to perform a brute force attack.

Updated: 2017-10-24

1.4.3 Keeping online systems safe

Phishing quiz

Phishing Quiz Game

SonicWALL Phishing IQ Test is a quiz game which is a great way to test students' understanding of phishing scams. Players are presented with a series of mock emails, web pages, or URLs that utilize some of the techniques online criminals often use. Spotting the the genuine pages and avoiding the fakes is harder than you might think!

Two more excellent resources are Microsoft's How to Recognize Phishing Messages and the Anti-Phishing Working Group, which both have a lot of up to date advice on avoiding phishing scams.

Updated: 2015-04-10

1.4.4 Application to real-life scenarios