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'Unbreakable' encryption system unveiled
A new ‘unbreakable’ encryption system is another step closer, according to a report on the BBC website, after the launch of the world’s first computer network protected by quantum encryption at a scientific conference in Vienna.
Quantum cryptography is completely different from the kinds of security schemes used on computer networks today. These are typically based on complex mathematical procedures that are extremely hard for outsiders to crack but not impossible given sufficient computing resources or time.
But quantum systems use the laws of quantum theory, which have been shown to be inherently unbreakable. The basic idea of quantum cryptography was worked out 25 years ago by Charles Bennett of IBM and Gilles Brassard of Montreal University, who was in Vienna to see the network in action.
"All quantum security schemes are based on the Heisenberg Uncertainty Principle, on the fact that you cannot measure quantum information without disturbing it," he explained.
"Because of that, one can have a communications channel between two users on which it's impossible to eavesdrop without creating a disturbance. An eavesdropper would create a mark on it. That was the key idea."
In practice this means using the ultimate quantum objects: photons, the "atoms of light". Incredibly faint beams of light equating to single photons fired a million times a second raced between the nodes in the Vienna network.
Each node, housed in a different Siemens office (Siemens has provided the fibre links), contains a small rack of electronics - boxes about the size of a PC - and a handful of sensitive light detectors.
From the detected photons, a totally secret numerical key can be distilled, which encodes the users' data much like the keys used in normal computer networks do. The advantage is that no-one else can know the key without revealing themselves.
To read the entire article click here to read it on the BBC's website.
