Bonus Level: The start 2025

Over the next few pages we’ll look at how computers can be used to encode and decode – computers have revolutionised codes – the ability to brute force through a large number of possibilities very quickly means that most codes from history are no longer secure.

I will look at how to use some basic Python codes I’ve made, but please note that I am no more than an interested amateur when it comes to coding – it will certainly be the case that there are more elegant or more efficient ways of coding the following examples. However hopefully because these are quite simplistic they should be easier to understand than some other examples from other sources.

For those with an interest in a deeper dive into using computers to crack codes, then the excellent: Cracking Codes with Python (Al Sweigart) is well worth a read.

I have deliberately left the codes in a form that means you won’t be able to copy and paste – the simple act of having to type and ensure accuracy and spacings is part of the skill.

Unlike in the other levels this it quite easy to cheat – by solving without needing to use Python code, but doing it properly will be much more rewarding.

The Python codes we’ll look at will be:

1. Reversing text
2. Atbash cipher
3. Frequency analysis
4. Transposition cipher
5. Caesar shift

If your school has paid the admin fee then your teachers will have been provided with the password to access this.