Prof. Ekert's main research interest is information processing in quantum-mechanical systems. It is a cross-disciplinary field bringing together theoretical and experimental quantum physics, mathematics, logic, computer science and information theory. His work is mostly theoretical but its results bear directly on issues of experimental implementation. One reason why it has attracted attention from industry and government agencies is that quantum cryptography can guarantee perfectly secure communication. Another is that projected quantum computers will be capable of efficiently solving some problems for which there is believed to be no efficient classical algorithm.