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Scheme of eavesdropping experiment on a quantum cryptography system (2009)


This experiment has demonstrated that it is possible to build a working eavesdropper Eve, which exploits technological imperfections in legitimate parties’ quantum cryptographic equipment. The particular imperfection exploited here is controllability of single-photon detectors. In this experiment, Eve has learned 100% of the secret key information without revealing her presence to the communicating parties. The experiment was done on a quantum cryptography system developed at the Centre for quantum technologies, Singapore. The eavesdropping equipment was built jointly by researchers from the Quantum Hacking group at the Norwegian University of Science and Technology, and the abovementioned centre.

The transmission line between the sender Alice and the receiver Bob consisted of fiber-optic cable laid through four buildings on campus of the National University of Singapore. Alice was located at the Centre for quantum technologies while Bob was in the office of the Physics Department. Eve was in another building between them.

Images used: Alice Alice’s setup Bob Bob’s setup Eve Eve’s setup.

This picture from Full eavesdropping on quantum cryptography gallery and Quantum hacking lab gallery is included in Picture Collection on Photo Pages.

The experiment took place on July 4–5, 2009.
This scheme was first used in a lecture “How we eavesdropped 100% of a quantum cryptographic key” given at Hacking at Random conference (2009). Download the entire presentation containing this scheme: PowerPoint (16.1 MiB).

How you can use this image. ©2009 Vadim Makarov. The background satellite image is ©2009 DigitalGlobe, thus you may also need a permission from them.

Vadim Makarov