in chemistry from Brandeis University in 1964 and received his PhD from Harvard in 1970 for molecular-dynamics studies (computer simulation of molecular motion) under David Turnbull and Berni Alder.

After joining IBM Research in 1972, he built on the work of IBM's Rolf Landauer to show that general-purpose computation can be performed by a logically and thermodynamically reversible apparatus; and in 1982 he proposed a re-interpretation of Maxwell's demon, attributing its inability to break the second law to the thermodynamic cost of destroying, rather than acquiring, information.

In collaboration with Gilles Brassard of the Université de Montréal, Bennett developed a system of quantum cryptography, building on an idea of Stephen Wiesner.

Known as BB84, the system takes advantage of the uncertainty principle to allow secure communication between parties who share no secret information initially.

[8] Bennett also co-runs a blog, The Quantum Pontiff, with Steve Flammia and Aram Harrow and hosted by Dave Bacon.