Charles Bennett is a computer scientist in IBM's Physics of Information group. He continues the work of logically and thermodynamically reversible computing, in which entropy increases are limited to the final storage of information, which in turn implies erasure of some storage media. This is known as Landauer's Principle. Bennett does not discuss the underlying physics of irreversibility. With Gilles Brassard, Bennett developed the field of quantum cryptography, which uses entangled quantum two-particle systems to generate and distribute encryption keys and allow two parties to communicate messages that are secure against eavesdropping by third parties. Their quantum key distribution scheme is called BB84 Bennett is one of the leaders in the new field of quantum information theory.