Quantum Cryptography: Is Your Data Safe Even When Somebody Looks?

The peculiar nature of the theory of quantum mechanics has furrowed the brow of even the greatest physicists. According to quantum theory, objects exist as a superposition of their possible states and take on one of these physical states with a certain probability only once they are subjected to a measurement. Albert Einstein felt compelled by this aspect of quantum theory to object that 'G-d does not play dice' (with nature) and during a heated philosophical discussion with a friend suddenly turned and asked if his friend really believed the moon was there only when somebody looks. While scientists and philosophers continue to ponder the very deep philosophical questions raised by quantum mechanics clever strategies (if not practical systems) have been devised to use these quantum mechanical properties to potentially perform computational feats not possible with classical computing systems. While for the most part quantum computing devices are decades away (at least) from being practical in the area of quantum cryptography - in particular the secure distribution of cryptographic keys - there exist strategies and systems that are feasible (perhaps even practical) today.