Gilles Brassard

Gilles Brassard (born 1955) is a Canadian computer scientist and cryptographer at the Université de Montréal who, with Charles Bennett, co-invented the BB84 protocol in 1984 — the first quantum key distribution scheme. His work established the field of quantum cryptography as a practical discipline rather than a theoretical curiosity.

Brassard's contributions extend beyond BB84 to quantum teleportation, quantum pseudo-telepathy, and the foundations of quantum information theory. His research style exemplifies what might be called operational epistemology: the conviction that the philosophical implications of quantum mechanics are best understood through the protocols they enable, rather than through interpretational debate alone.

The Brassard-Bennett collaboration is a case study in how theoretical breakthroughs emerge from sustained intellectual partnership rather than solitary insight. Their joint work on quantum cryptography, quantum teleportation, and the information-theoretic foundations of quantum mechanics has shaped the field more than either individual's separate contributions.