Breaking a quantum key distribution system through a timing side channel.

The security of quantum key distribution relies on the validity of quantum mechanics as a description of nature and on the non-existence of leaky degrees of freedom in the practical implementations. We experimentally demonstrate how, in some implementations, timing information revealed during public discussion between the communicating parties can be used by an eavesdropper to undetectably access a significant portion of the "secret" key.

[1]  Dag R. Hjelme,et al.  Faked states attack on quantum cryptosystems , 2005 .

[2]  H. Bechmann-Pasquinucci,et al.  Quantum cryptography , 2001, quant-ph/0101098.

[3]  A. Zeilinger,et al.  Practical quantum key distribution with polarization entangled photons , 2005 .

[4]  H. Weinfurter,et al.  Free-Space distribution of entanglement and single photons over 144 km , 2006, quant-ph/0607182.

[5]  Jian-Wei Pan,et al.  Experimental free-space distribution of entangled photon pairs over 13 km: towards satellite-based global quantum communication. , 2005, Physical review letters.

[6]  Christine Chen,et al.  Quantum hacking: Experimental demonstration of time-shift attack against practical quantum-key-distribution systems , 2007, 0704.3253.

[7]  Ekert,et al.  Quantum cryptography based on Bell's theorem. , 1991, Physical review letters.

[8]  N. Gisin,et al.  Trojan-horse attacks on quantum-key-distribution systems (6 pages) , 2005, quant-ph/0507063.

[9]  P R Tapster,et al.  Quantum cryptography: A step towards global key distribution , 2002, Nature.

[10]  J. Skaar,et al.  Effects of detector efficiency mismatch on security of quantum cryptosystems , 2005, quant-ph/0511032.

[11]  Gilles Brassard,et al.  Quantum Cryptography , 2005, Encyclopedia of Cryptography and Security.

[12]  Christian Kurtsiefer,et al.  Free-space quantum key distribution with entangled photons , 2006 .

[13]  Philip Walther,et al.  Distributing entanglement and single photons through an intra-city, free-space quantum channel , 2005 .

[14]  Gilles Brassard,et al.  Privacy Amplification by Public Discussion , 1988, SIAM J. Comput..