Crack open a program with Ghidra, the NSA's free tool
Ghidra is the reverse-engineering tool the NSA built and then gave away for free. In this mission you build a tiny password-locked program yourself, then use Ghidra to read its compiled code, recover the password it was hiding, and patch the lock out entirely. Nothing illegal, nothing online: it's your program on your own machine.
- Windows 11 (Ghidra runs on Mac and Linux too, but the commands here are for Windows)
- About 1.5GB of free disk space (Ghidra is a 543MB download, the Java it needs is another 200MB)
- A terminal. We use Windows PowerShell, which is already on your PC. No admin rights needed for any of this
What you're about to do, and why it's legal
Understand what reverse engineering is before you touch the tool, so you stay on the right side of the line.
Every program you run is just a file full of numbers the processor understands. Reverse engineering is reading those numbers back into something a human can follow: the logic, the strings, the checks. It's how antivirus firms study malware, how researchers find security holes, and how people work out why an old program broke.
Ghidra is the tool for it. The US National Security Agency built it in-house, then released it as free, open-source software in 2019. It's genuinely the real thing, not a toy version, and it costs nothing.
Here's the important part. Taking apart software can break copyright law or the licence agreement you clicked past when you installed it. So in this mission you'll reverse engineer a program you wrote and compiled yourself. You own it completely, which makes it entirely lawful, and it's small enough to understand every byte of. When you move on to other programs later, that's on you: check you're allowed first. Ghidra's own startup screen says the same thing.
CarefulReverse engineering a program you don't own or have permission to study can be illegal where you live. Practise on your own code, on open-source code, or on something you've been given written permission to test. Never on cracking paid software to avoid paying for it.