摘要Recently, Boyer et al. presented a novel semiquantum key distribution protocol [Phys. Rev. Lett. 99 (2007) 140501] by using four quantum states, each of which is randomly prepared in the Z or X basis. Here we present a semiquantum key distribution protocol by using maximally entangled states in which quantum Alice shares a secret key with classical Bob. Quantum Alice has the ability to prepare Bell states and perform Bell basis or computational basis measurement. Classical Bob is restricted to measuring, preparing a particle in the computational basis, reflecting or reordering the particles. The qubit efficiency of the protocol improves to 50% and the protocol can be modified to a measure-resend protocol or a protocol without quantum memory. We also show that the protocol is secure against eavesdropping.
Abstract：Recently, Boyer et al. presented a novel semiquantum key distribution protocol [Phys. Rev. Lett. 99 (2007) 140501] by using four quantum states, each of which is randomly prepared in the Z or X basis. Here we present a semiquantum key distribution protocol by using maximally entangled states in which quantum Alice shares a secret key with classical Bob. Quantum Alice has the ability to prepare Bell states and perform Bell basis or computational basis measurement. Classical Bob is restricted to measuring, preparing a particle in the computational basis, reflecting or reordering the particles. The qubit efficiency of the protocol improves to 50% and the protocol can be modified to a measure-resend protocol or a protocol without quantum memory. We also show that the protocol is secure against eavesdropping.
[1] Bennett C H and Brassard G 1984 Proc. IEEE Int. Conf. on Computers, Systems and signal Processing (Bangalore, India) (New York: IEEE) p 175
[2] Bennett C H 1992 Phys. Rev. Lett. 68 3121
[3] Bechmann-Pasquinucci H and Peres A 2000 Phys. Rev. Lett. 85 3313
[4] Bruss D 1998 Phys. Rev. Lett. 81 3018
[5] Ekert A K 1991 Phys. Rev. Lett. 67 661
[6] Bennett C H, Brassard G and Mermin N D 1992 Phys. Rev. Lett. 68 557
[7] Curty M, Lewenstein M and Lutkenhaus N 2004 Phys. Rev. Lett. 92 217903
[8] Boyer M, Kenigsberg D and Mor T 2007 Phys. Rev. Lett. 99 140501
[9] Boyer M, Gelles R, Kenigsberg D and Mor T 2009 Phys. Rev. A 79 032341
[10] Lu H and Cai Q Y 2008 Int. J. Quantum Inform. 6 1195
[11] Zou X, Qiu D, Li L, Wu L and Li L 2009 Phys. Rev. A 79 052312
[12] Li Q, Chan W H and Long D Y 2010 Phys. Rev. A 82 022303
[13] Tan Y G, Lu H and Cai Q Y 2009 Phys. Rev. Lett. 102 098901
[14] Stinespring W F 1955 Proc. Am. Math. Soc. 6 211
[15] Inamori H, Rallan L and Vedral V 2001 J. Phys. A 34 6913
2011, Vol. 28 
