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SYDNEY: Banks, the military and digital media distributors could benefit from a novel method of secure online communication that uses quantum encryption but can also ensure the message is only received by the right person, in the right place.
The new technique is at the hypothetical stage but could be applied to current communications networks, says its inventor, Australian telecommunications researcher Robert Malaney from the University of New South Wales in Sydney.
Malaney's system is based on quantum encryption, which uses a weird property of quantum particles to ensure that coded information cannot be copied.
'Entangled' photons encode message
Unlike classical particles, which must exist in a certain state, such as zero or one, quantum information particles, called qubits, can exist in a superposition of states, according to Malaney.
A pair of qubits consists of a pair of photons which are 'entangled' in that measuring the state of one photon exerts an influence on the state of the other photon. In Malaney's system information is encoded into a pair of entangled photons.
"In quantum mechanics it's impossible to copy the information encoded in the entangled photons," he said. "It is also impossible to decode the information unless you have both the entangled photons."
defrauding current quantum encryption
Current quantum encryption techniques, such as those used by some governments, rely on entangled photons being sent through fibre optic cables. The encryption key to encode and decode the information is constructed using the entangled photons and other information sent through classical channels such as wireless Internet.
But it's still possible for people to defraud the current system because there is no fool-proof authentication on where the receivers are.
"What's new here is current networks don't know who you are or, more importantly, where you are," Malaney told Cosmos. "When someone is claiming to be a server at a bank in Sydney they may actually be at a garage in Moscow."
Malaney's system, described in the journal Physical Review A, relies on the fact that in the first place, quantum techniques can code the signal so that it can't be copied. Secondly, the receiver of the quantum information sends a reply using information from the decoded qubits over classical wireless technology to a number of reference points.
