compilers HATE him: use this ONE WEIRD TRICK to hide a message in your x86 program!! by William Woodruff Steganography is the art of hiding (not encrypting!) messages within otherwise inconspicuous data. Typical steganographic techniques involve media formats: images, movies, and audio. But what if we can hide messages within compiled programs themselves?? This talk will go through a whirlwind tour of steganography and the x86 architecture, and then show you ONE WEIRD TRICK in x86’s instruction encoding that allows us to do exactly that! William Woodruff is a security researcher at Trail of Bits, primarily doing DARPA-funded research into program (LLVM) and binary (x86) analysis. During his free time, he likes to blog, ride bicycles, and do a bit of open source work (most recently in Rust). He’s slowly working on completing the system of German Transcendental Idealism.