Unit tests check that your code does the right thing for specific inputs you thought of. Property-based tests check that your code does the right thing for hundreds or thousands of inputs the compu...
Every module on a YubiKey has its own PIN, its own retry limit, and its own consequences when you get it wrong too many times. Some lock you out of a single function. Others wipe the entire module....
TLA+ is a formal specification language for designing and verifying concurrent and distributed systems. PlusCal is an algorithm language that compiles to TLA+, giving you a more familiar imperative...
You know what the kernel does. You know what GNOME does. But how does a framebuffer in kernel memory become pixels managed by Mutter? How does a USB interrupt from your keyboard become a keypress i...
This is a walkthrough of building a working Linux desktop environment entirely from source — the kernel, Xorg display server, and a full GNOME desktop with its filesystem stack. No package manager,...
The GPG fundamentals post covered key hierarchy, subkey generation, and YubiKey integration. This post goes deeper — Web of Trust mechanics, subkey rotation without breaking trust, air-gapped prima...
The first post covered the YubiKey 5C modules and basic hardening. The GPG post walked through subkeys and OpenPGP integration. This post goes deeper — PIV-based SSH and TLS, FIDO2 resident keys, d...
GPG (GNU Privacy Guard) is the open-source implementation of the OpenPGP standard. It handles encryption, signing, and authentication using a hierarchical key structure. Pairing it with a YubiKey m...
The YubiKey 5C is a USB-C hardware security key from Yubico that packs multiple cryptographic modules into a single device. Each module serves a distinct purpose, and understanding them is key to g...