Don’t Panic: A Codebreaker’s Guide to Getting Unstuck
The Hitchhiker’s Guide to the Galaxy is, among other things, a book designed to help its reader navigate a universe that is confusing, chaotic, and occasionally hostile. This guide has far more modest ambitions: to help you remain at least somewhat functional while staring at a block of ciphertext that appears to have been designed specifically to ruin your evening. If there is one thing worth remembering throughout the rest of this guide, it is the same advice printed in large, friendly letters on the cover of the Hitchhiker’s Guide: DON’T PANIC
1 What This Guide Is (and Isn’t)
This is not a guide on how to break codes.
There are plenty of places you can go if what you want is the mechanics: how to run frequency analysis, how to implement a hill-climb attack, or which button to press next in Python. If that’s what you’re looking for, this guide will probably feel a bit frustrating.
This is a guide on how to be a codebreaker. Or at least, a guide I wish I had when I first started.
It’s about what to do before you know what cipher you’re even looking at. How to think when nothing makes sense yet, how to recognise progress when there is no readable plaintext in sight, and how to stay functional and vaguely sane when you’re stuck, because at some point, you absolutely will be.
Codebreaking, especially with something like the National Cipher Challenge, is very rarely a neat sequence of steps. More often than not, it’s long periods of uncertainty sprinkled with small insights that only feel obvious in hindsight.
Most of the difficulty in codebreaking comes from uncertainty like not knowing where to start, whether you’re making progress, or whether the idea you’re attached to is actually helping.
In short, if you’ve ever stared at a block of ciphertext and thought to yourself, I have no idea what I’m doing, then you’re in the right place.
You can download the full PDF version of this guide here: