Hackers blinded by the light

Scientists from Toshiba's research division, collaborating with the University of Cambridge, have made a discovery that may bring the concept of quantum encryption closer to reality.

The development of a Light Emitting Diode (LED) capable of firing a single photon, has prompted researchers to say the technology could be applied to optical communications as a security measure.

Quantum cryptography is one of the technologies the single photon source could be applied to.

The attraction of quantum cryptography is that fundamental laws of nature guarantee security, as any attempt by a hacker to read the single photon signals can be detected by the sender and intended recipient.

And in contrast to methods based on codes, the keys formed by quantum cryptography can, in principle, be completely uncrackable. The key is also changed every time.

Dr Andrew Shields, leader of the research, said: "A single photon source is a building block for a wide range of applications in quantum information technology, of which secure optical communications is the most immediate."

The researchers said that until now, quantum cryptography has not been fail-safe because conventional light-emitting diodes and lasers sometimes produce two or more photons, which could allow a hacker to determine parts of the key without detection.

The creation of a single photon emitting LED solves this problem.

Managing director the Cambridge Research Laboratory, professor Michael Pepper, said: "Single photons are rather like the magic bullets in molecular biology, in that the laws of quantum mechanics result in the certain failure of any attempt to intercept the information."