Logic & Philosophy of Science

In recent years, following pioneering work by Richard Feynman and David Deutsch, there has been an explosive development in research on quantum information, quantum computation, and quantum cryptography. Quantum computers exploit the essentially non-classical features of so-called 'entangled' quantum states, first identified by Einstein, Podolsky, and Rosen in a celebrated argument for the incompleteness of quantum mechanics. Cryptography is the science of securely communicating and authenticating information. The aim of quantum cryptography is to identify procedures that are guaranteed to be absolutely secure against eavesdropping or cheating by the laws of quantum physics, even if all parties have access to quantum computers. I review some of the developments in the field, with particular attention to the role of entanglement in allowing certain procedures and in thwarting others.