title: Security of modified Ping-Pong protocol in noisy and lossy channel.
abstract: The "Ping-Pong" (PP) protocol is a two-way quantum key protocol based on entanglement. In this protocol, Bob prepares one maximally entangled pair of qubits, and sends one qubit to Alice. Then, Alice performs some necessary operations on this qubit and sends it back to Bob. Although this protocol was proposed in 2002, its security in the noisy and lossy channel has not been proven. In this report, we add a simple and experimentally feasible modification to the original PP protocol, and prove the security of this modified PP protocol against collective attacks when the noisy and lossy channel is taken into account. Simulation results show that our protocol is practical.
authors.affiliation: 1] Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China [2] Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China [3].
authors.forename: Yun-Guang
authors.initials: YG
authors.lastname: Han
authors.affiliation: 1] Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China [2] Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China [3].
authors.forename: Zhen-Qiang
authors.initials: ZQ
authors.lastname: Yin
authors.affiliation: 1] Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China [2] Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Li
authors.affiliation: 1] Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China [2] Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: 1] Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China [2] Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Wang
authors.affiliation: 1] Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China [2] Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Guang-Can
authors.initials: GC
authors.lastname: Guo
authors.affiliation: 1] Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei 230026, China [2] Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Zheng-Fu
authors.initials: ZF
authors.lastname: Han