Turing Award Bestowed for Quantum Informatics Achievements for the First Time

Charles Bennett and Gilles Brassard spent the 1980s arguing that quantum mechanics could solve a problem classical cryptography couldn't: how to establish a secret key between two parties with security guaranteed by physics rather than computational assumptions. This week, the ACM agreed, awarding them the 2025 Turing Award — the first time computing's highest honor has gone to quantum information science.

The prize, $1 million with Google backing, recognizes work that took decades to become practical. In 1984, Bennett (IBM Research, where he's worked since 1973) and Brassard (Université de Montréal) published the BB84 protocol — a scheme for quantum key distribution that lets two parties create an encryption key with information-theoretic security. Any eavesdropping attempt disturbs the quantum states being transmitted, and that disturbance is detectable before any information is compromised. No quantum computer required on the sending end. No computational hardness assumption. Just physics.

The catch, then as now: you need working quantum hardware. In 1984, that was a thought experiment. Bennett and Brassard had demonstrated something theoretically elegant but experimentally empty. Quantum cryptography networks — fiber-based landlines and satellite links — took decades to build. Variants of BB84 are now deployed operationally, including via China's Micius satellite and Europe's quantum communication infrastructure programs. But the broader quantum internet remains a roadmap, not a reality.

What changed the calculus was Peter Shor's 1994 algorithm. A sufficiently powerful quantum computer could break RSA and Diffie-Hellman — the mathematical backbone of modern internet encryption — in polynomial time. Suddenly, BB84 wasn't just theoretically interesting. It was the answer to an emerging threat. The race between building quantum computers capable of running Shor's algorithm at scale and deploying quantum key distribution infrastructure at scale is still unresolved. Large-scale fault-tolerant quantum computers remain years away. Quantum key distribution networks are real but limited in range and expensive to operate.

Bennett and Brassard's other contributions are equally foundational. Quantum teleportation, 1993 — demonstrating that an arbitrary quantum state could be transmitted using entanglement and classical communication, even though the quantum state itself can't be copied. Entanglement distillation, 1996 — showing how weak entanglement could be strengthened into high-quality entanglement, a prerequisite for quantum networks. Experimental verification of teleportation and related phenomena earned the 2022 Nobel Prize in Physics. The conceptual architecture those ideas built is now core to quantum networking and the pursuit of a quantum internet.

The International Year of Quantum Science and Technology — designated by the United Nations for 2025 — provides a convenient frame, but the recognition of Bennett and Brassard isn't symbolic. Their work defined the vocabulary the entire quantum industry now uses. QKD networks, quantum repeaters, the entanglement-based protocols that satellite and fiber networks depend on — it all traces back to BB84.

The practical question for 2026: does the award accelerate investment in quantum-safe infrastructure, or is it a retrospective honor for a problem that hasn't fully arrived yet? Bennett and Brassard built the foundation. The building is still under construction.

The ACM award announcement is here: https://www.prnewswire.com/news-releases/acm-am-turing-award-honors-charles-h-bennett-and-gilles-brassard-for-foundational-contributions-to-quantum-information-science-302716290.html

IBM's profile of Bennett is here: https://newsroom.ibm.com/2026-03-18-ibm-fellow-and-quantum-pioneer-charles-h-bennett-receives-a-m-turing-award-computings-highest-honor