Frankfurt 2006 – scientific programme

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Q: Quantenoptik und Photonik

Q 58: Quantenkommunikation

Q 58.3: Talk

Thursday, March 16, 2006, 11:40–11:55, HVI

Practical quantum key distribution with two-way classical communication — •Aeysha Khalique, Georgios M. Nikolopoulos, and Gernot Alber — Institut für Angewandte Physik, Technische Universität Darmstadt, D-64289 Darmstadt.

We investigate the key generation rates and achieveable distances for conventional Bennett-Brassard and six state protocols under realistic conditions using two-way purification protocols and Calderbank-Shor-Steane codes. In particular, we analyse the photon number splitting attack where legitimate users lack single photon sources and have lossy channels and inefficient detectors. Our analysis shows that two-way classical communication protocols increase the distance up to which a secret key can be distilled without compromising much on the key generation rate. Two-way classical communication protocols also help to suppress the sudden dip in key generation rate due to dark counts.

[1] D. Gottesman, H-K Lo, N. Lütkenhaus and J. Preskill, Quant. Inf. and Comp. 4, 325 (2004).

[2] D. Gottesman, H.-K. Lo, IEEE Trans. Inf. Th. 49, 457 (2003).

[3] A. Khalique, Georgios M. Nikolopoulos and G. Alber (in preparation).