Security innovator. I like to look at hard security problems, look at them from outside the box, and create solutions that let us have our cake and eat it too.
Invented the Stack Canary (StackGuard) in 1997 to block stack smashing buffer overflow vulnerabilities. This defense is now used on nearly all computers in the world.
Created AppArmor, a mandatory access control system for Linux that system administrators *don't* hate, because it is easy to use and uses shell-like notations.
Collaborated with the NSA to create LSM (Linux Security Modules) interface that allows Linux to have mandatory access controls.
Designed the app container sandbox for Microsoft Windows, used as the sandbox for Windows Store apps, and for the Microsoft Edge browser.
Some of my security work is running in nearly every computer platform, with the exception of old, pre-Internet mainframes.