Researchers at the University of Waterloo's Institute for Quantum Computing (IQC) say they have developed the first available software to evaluate the security protocol for Quantum Key Distribution (QKD), which enables two parties to establish a shared secret key by exchanging photons.
If an eavesdropper intercepts and measures the photons, it will cause a disturbance that is detectable to the original secret-sharing parties; if there is no disturbance, the original parties can guarantee the security of the shared key.
In practice, loss and noise in an implementation always results in some disturbance, but a small amount of disturbance implies a small amount of information about the key is available to the eavesdropper. Characterizing this amount of information enables it to be removed at the cost of the length of the resulting key, but the main theoretical problem with QKD is how to calculate the allowed length of the final secret key for any given protocol and the experimentally observed disturbance. The IQC researchers addressed this problem with a numerical approach, transforming the key rate calculation to the dual optimization problem.
The researchers tested the software against previous results for known studied protocols, and found their results were in perfect agreement.
From University of Waterloo
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