Research Interests Computer and network security Principles of programming languages Specification and verification methods
He is well known for his work on computer security and on programming languages, including his paper (with Michael Burrows and Roger Needham) on the Burrows–Abadi–Needham logic for analyzing authentication protocols, and his book (with Luca Cardelli) A Theory of Objects, laying out formal calculi for the semantics of object-oriented programming languages.
In 1993, he published the programming language Baby Modula-3, a safe subset or sublanguage of Modula-3, based on functional programming and set theory ideals.