Charles Bennett of IBM and Gilles Brassard of the University of Montreal have won the 2025 Turing Award for their groundbreaking work in quantum cryptography. The duo's 1984 protocol, known as BB84, became the foundation for quantum key distribution — a method of secure communication that uses quantum mechanics to detect eavesdropping attempts. Their theoretical breakthrough has evolved into practical systems now protecting sensitive data across government and financial networks worldwide.
The Association for Computing Machinery announced the award Wednesday, citing Bennett and Brassard's "foundational contributions to quantum cryptography and quantum information science." The recognition comes as quantum technologies transition from laboratory curiosities to commercial realities.
Bennett, now 78, began exploring quantum cryptography in the early 1980s while working at IBM's Thomas J. Watson Research Center. His collaboration with Brassard, then a young computer scientist at the University of Montreal, produced a paper that initially drew limited attention from the broader scientific community.
"We knew we had something interesting, but we didn't anticipate it would become the foundation for an entire industry," Bennett reflected in a 2019 interview. The protocol they developed exploits a core principle of quantum mechanics: measuring a quantum system inevitably disturbs it.
The practical applications have expanded far beyond what the researchers originally envisioned. Today, quantum key distribution systems secure communications for banks, government agencies, and critical infrastructure operators. China has deployed a quantum communication satellite, while European researchers operate quantum networks spanning hundreds of kilometers.
The Turing Award, often called the "Nobel Prize of computing," comes with a $1 million prize funded by Google. Previous recipients include pioneers of the internet, artificial intelligence, and computer graphics. Bennett and Brassard join a distinguished list that includes Tim Berners-Lee, who created the World Wide Web, and Geoffrey Hinton, known as the "godfather of deep learning."
Brassard, 71, has spent decades advancing the theoretical foundations of quantum information science beyond cryptography. His work spans quantum algorithms, quantum complexity theory, and the limits of quantum computation. The Montreal researcher has trained a generation of quantum scientists who now lead research groups worldwide.
The timing of the award reflects quantum cryptography's growing strategic importance. As traditional encryption methods face potential threats from quantum computers capable of breaking current security protocols, quantum key distribution offers a path to "quantum-safe" communications.
Major technology companies have invested heavily in quantum cryptography startups. ID Quantique, Toshiba, and MagiQ Technologies now manufacture commercial quantum key distribution systems. Banks in Switzerland and Austria use quantum-secured networks for high-value transactions, while government agencies in multiple countries have deployed similar systems.
- Quantum teleportation protocols enabling quantum computing networks
- Quantum random number generators for cryptographic applications
- Theoretical frameworks for quantum error correction and fault tolerance
- Foundational work supporting quantum internet development
The award also recognizes the researchers' broader contributions to quantum information theory. Their work helped establish quantum mechanics as a resource for computation and communication, not just a description of physical phenomena. This conceptual shift opened entirely new fields of research and technological development.
Bennett and Brassard will formally receive the award at the ACM's annual banquet in June. Their acceptance speeches are expected to address quantum security developments and their implications for cybersecurity in an increasingly connected world.