Practical Quantum Key Distribution with Non-Phase-Randomized Coherent States

Quantum key distribution (QKD) based on coherent states is well known for its implementation simplicity, but it suffers from loss-dependent attacks based on optimal unambiguous state discrimination. Crucially, previous research has suggested that coherent-state QKD is limited to short distances, typically below 100 km assuming standard optical fiber loss and system parameters. In this work, we propose a six-coherent-state phase-encoding QKD protocol that is able to tolerate the total loss of up to 38 dB assuming realistic system parameters, and up to 56 dB loss assuming zero noise. The security of the protocol is calculated using a recently developed security proof technique based on semi-definite programming, which assumes only the inner-product information of the encoded coherent states, the expected statistics, and that the measurement is basis-independent. Our results thus suggest that coherent-state QKD could be a promising candidate for high-speed provably-secure QKD.

[1]  H. Lo,et al.  Practical Decoy State for Quantum Key Distribution , 2005, quant-ph/0503005.

[2]  Le Phuc Thinh,et al.  Security of distributed-phase-reference quantum key distribution. , 2012, Physical review letters.

[3]  Won-Young Hwang.  Quantum key distribution with high loss: toward global secure communication. , 2003, Physical review letters.

[4]  Yoshihisa Yamamoto,et al.  Practical quantum key distribution protocol without monitoring signal disturbance , 2014, Nature.

[5]  M. Curty,et al.  Secure quantum key distribution , 2014, Nature Photonics.

[6]  Jos F. Sturm,et al.  A Matlab toolbox for optimization over symmetric cones , 1999 .

[7]  J. Skaar,et al.  Hacking commercial quantum cryptography systems by tailored bright illumination , 2010, 1008.4593.

[8]  Yi Zhao,et al.  Experimental quantum key distribution with active phase randomization , 2006, quant-ph/0611059.

[9]  Hoi-Kwong Lo,et al.  Effect of source tampering in the security of quantum cryptography , 2015, 1508.05258.

[10]  M. Curty,et al.  Measurement-device-independent quantum key distribution. , 2011, Physical review letters.

[11]  J. F. Dynes,et al.  Robust random number generation using steady-state emission of gain-switched laser diodes , 2014, 1407.0933.

[12]  Fei Gao,et al.  Reduced gap between observed and certified randomness for semi-device-independent protocols , 2015 .

[13]  Nicolas Brunner,et al.  Certifying the dimension of classical and quantum systems in a prepare-and-measure scenario with independent devices. , 2013, Physical review letters.

[14]  Erik Woodhead,et al.  Secrecy in Prepare-and-Measure Clauser-Horne-Shimony-Holt Tests with a Qubit Bound. , 2015, Physical review letters.

[15]  Shuang Wang,et al.  Experimental demonstration of a quantum key distribution without signal disturbance monitoring , 2015, Nature Photonics.

[16]  F. Bussières,et al.  Secure Quantum Key Distribution over 421 km of Optical Fiber. , 2018, Physical review letters.

[17]  Horace P. Yuen,et al.  Quantum amplifiers, quantum duplicators and quantum cryptography , 1996 .

[18]  Miloslav Dusek,et al.  Unambiguous state discrimination in quantum cryptography with weak coherent states , 2000 .

[19]  Erik Woodhead,et al.  Semi-device-independent framework based on natural physical assumptions , 2016, 1612.06828.

[20]  V. Scarani,et al.  The security of practical quantum key distribution , 2008, 0802.4155.

[21]  Atsushi Okamoto,et al.  Evaluation of the phase randomness of a light source in quantum-key-distribution systems with an attenuated laser , 2014, 1407.1588.

[22]  Matthias Christandl,et al.  Postselection technique for quantum channels with applications to quantum cryptography. , 2008, Physical review letters.

[23]  Tsuyoshi Murata,et al.  {m , 1934, ACML.

[24]  Antonios Varvitsiotis,et al.  Characterising the correlations of prepare-and-measure quantum networks , 2018, npj Quantum Information.

[25]  H. Inamori,et al.  Unconditional security of practical quantum key distribution , 2007 .

[26]  Masato Koashi,et al.  Experimental quantum key distribution without monitoring signal disturbance , 2015, Nature Photonics.

[27]  Xiang‐Bin Wang,et al.  Beating the PNS attack in practical quantum cryptography , 2004 .

[28]  Nicolas Brunner,et al.  Semi-device-independent security of one-way quantum key distribution , 2011, 1103.4105.

[29]  Chun-Yan Li,et al.  Partially random phase attack to the practical two-way quantum-key-distribution system , 2012, 1305.5985.

[30]  Hoi-Kwong Lo,et al.  Loss-tolerant quantum cryptography with imperfect sources , 2013, 1312.3514.

[31]  Xiongfeng Ma,et al.  Decoy state quantum key distribution. , 2004, Physical review letters.

[32]  Go Kato,et al.  Differential-phase-shift quantum-key-distribution protocol with a small number of random delays , 2017, 1702.00162.

[33]  Hoi-Kwong Lo,et al.  Experimental quantum key distribution with source flaws , 2015 .

[34]  Zhu Cao,et al.  Discrete-phase-randomized coherent state source and its application in quantum key distribution , 2014, 1410.3217.

[35]  Jian-Wei Pan,et al.  Source attack of decoy-state quantum key distribution using phase information , 2013, 1304.2541.

[36]  Shi-Hai Sun,et al.  Experimental demonstration of an active phase randomization and monitor module for quantum key distribution , 2012 .