I study programming languages and computer security. I have wide-ranging interests, and some of my most recent work touches on: Coq verification of LLVM program transformations and randomized algorithms, type-directed program synthesis, linear types and GUI programming. I have also spent a lot of time thinking about language-based enforcement of information-flow policies, low-level code memory safety, understanding dynamic security policies, and authorization logic. I am also interested in secure concurrent and distributed computing, functional programming languages, type theory, linear and modal logics, theorem proving and mechanized metatheory.