Quantum Cryptography

From Olpcaustria

Quantum cryptography is the oldest and best developed application of the field of quantum information science.

Although it is frequently perceived as an encryption method, it is really a scheme to securely distribute correlated random numbers between the communicating parties and thus better described as quantum key distribution (QKD).

Any attempt at eavesdropping from a third party is guarantied to be detected by the laws of physics (quantum mechanics) and shows up as an increased error rate in the transmission (the QBER).

QKD and the XO laptop

Prof. Christian Kurtsiefer, Prof. Antia Lamas and others from the

Quantum Information Technology Lab
Quantum Optics Section
Department of Physics
National University of Singapore
2 Science Drive 3
117542 Singapore

have been at the 24C3, giving a lecture on Quantum Cryptography and Possible Attacks (Lecture Video), and demonstrating the hardware of a full working kit developed in the National University of Singapore for entanglement based QKD over a free space channel.

That device is accessible via usb and was built up at the ccc on the on the first floor. They got interested in the xo, sj gave them a few to play, and they started implementing their software for quantum key distribution.

After a few hours of tinkering with the kernel config, timings (the xo's had to be synchronized with an accuracy of at least 0.5 sec) and the dependencies, the team successfully tested the first 'entanglement based quantum key distribution' between two xo laptops! (Sa, 29.12.07)

They enjoyed playing with the xo's, and never got tired answering questions. It was a great experience to meet them : )

Crazy-chris 16:14, 1 January 2008 (CET)

Update: My mistake. Only the synchronization was already working, the key exchange was not.

Crazy-chris 00:57, 16 January 2008 (CET)