Published in Physics World, 5 Sep 2013
Quantum cryptography is the most secure method of communication available – but it is also expensive, because each pair of users requires its own set of specialized equipment. That could soon change, however, now that physicists working at Toshiba have developed technology to allow up to 64 users to share the same transmission line.
In conventional cryptography one person, Alice, wants to send another person, Bob, an encrypted message. To do so she first sends him a “key” so that the message can be decrypted. But transmitting the key is a security hazard: an eavesdropper, Eve, could easily intercept it, read it and send it on, without Alice and Bob’s ever noticing. […]
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