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Laser Physics Letters

Measurement-free mediated semi-quantum key distribution protocol based on single-particle states

Shun Zhou, Qi-Ming Xie, Nanrun Zhou

Published May 2, 2024• 50 citations
Publisher

Abstract

Abstract A novel measurement-free mediated semi-quantum key distribution (MSQKD) protocol is proposed based on single-particle states. It enables two classical users to establish a secret key with the assistance of a third party. This protocol simplifies the third party’s role to solely generating qubits in X-basis and conducting Bell measurements. A distinctive feature of this protocol is the efficient grouping and reordering of qubits by the classical users with a minimum of three delay lines. Security analyses demonstrate that the protocol can withstand various attack strategies, including collective attack, measurement attack, fake state attack, and modification attack. The noise tolerance is given by deriving a lower bound of the protocol’s key rate in the asymptotic scenario. Simulations on the IBM Quantum Experience platform are conducted to illustrate the feasibility of this protocol. Compared with existing MSQKD protocols, the proposed protocol consumes fewer quantum resources and achieves a qubit efficiency of 1/8.

DOI
10.1088/1612-202x/ad3f96

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Abstract A novel measurement-free mediated semi-quantum key distribution (MSQKD) protocol is proposed based on single-particle states. It enables two classical users to establish a secret key with the assistance of a third party. This protocol simplifies the third party’s role to solely generating qubits in X-basis and conducting Bell measurements. A distinctive feature of this protocol is the efficient grouping and reordering of qubits by the classical users with a minimum of three delay lines. Security analyses demonstrate that the protocol can withstand various attack strategies, including collective attack, measurement attack, fake state attack, and modification attack. The noise tolerance is given by deriving a lower bound of the protocol’s key rate in the asymptotic scenario. Simulations on the IBM Quantum Experience platform are conducted to illustrate the feasibility of this protocol. Compared with existing MSQKD protocols, the proposed protocol consumes fewer quantum resources and achieves a qubit efficiency of 1/8.
In this paper, we propose a new efficient mediated semi-quantum key distribution (MSQKD) protocol, facilitating the establishment of a shared secret key between two classical participants with the assistance of an untrusted third party (TP). Unlike existing MSQKD protocols, our approach significantly reduces the quantum requirements for TP, who only needs to prepare and measure qubits in the XXX basis. Meanwhile, the classical participants are limited to preparing and measuring qubits in the ZZZ basis, along with performing Hadamard operations. This reduction in quantum overhead enhances the practicality of our MSQKD protocol without compromising qubit efficiency. Additionally, we demonstrate the security of our protocol against various well-known attacks.
Abstract Mediated semi-quantum key distribution (MSQKD) is a popular topic in quantum cryptography, which requires less quantum abilities from legitimate users, Alice and Bob, and has the advantage of high noise tolerance. In this paper, we propose a new MSQKD protocol where the third-party quantum server M can randomly send single-state and entangled-state without informing Alice and Bob of the type of qubit. In addition, in the case where M has an infinite quantum source, we derive the key rate and noise tolerance of the protocol, which proves the unconditional security of the protocol. Furthermore, as M changes the ratio of single-state and entangled-state, the noise tolerance also changes. In particular, when M sends only single-state or entangled-state, our protocol degenerates into the previous MSQKD protocols, and we derive a higher noise tolerance by analysing the mismatch terms.
The mediated semi-quantum key distribution (MSQKD) protocol is an important research issue that lets two classical participants share secret keys securely between each other with the help of a third party (TP). However, in the existing MSQKD protocols, there are two improvable issues, namely (1) the classical participants must be equipped with expensive detectors to avoid Trojan horse attacks and (2) the trustworthiness level of TP must be honest. To the best of our knowledge, none of the existing MSQKD protocols can resolve both these issues. Therefore, this study takes Bell states as the quantum resource to propose a MSQKD protocol, in which the classical participants do not need a Trojan horse detector and the TP is dishonest. Furthermore, the proposed protocol is shown to be secure against well-known attacks and the classical participants only need two quantum capabilities. Therefore, in comparison to the existing MSQKD protocols, the proposed protocol is better practical.
Abstract As quantum communication networks approach practical deployment, mediated semi-quantum key distribution (MSQKD) has attracted attention for enabling classical users to share keys via semi-honest servers. This paper proposes a cross-domain MSQKD protocol based on four-particle GHZ-like states. Two semi-honest servers prepare and transmit quantum sequences with decoy states, while users perform only Bell and single-photon measurements to derive shared keys. The protocol eliminates additional unitary operations, significantly reducing user-side quantum requirements, hardware costs, and implementation complexity. By exploiting entanglement correlations, it achieves a qubit efficiency of 42.86% and resists both external and internal attacks. The feasibility of the protocol is verified through simulations on Qiskit and the IBM quantum platform, demonstrating its practicality under current quantum technology.
Abstract In this paper, we propose an efficient lightweight mediated semi-quantum key distribution (LM-SQKD) protocol, which enables two lightweight participants to securely establish a shared key with the help of an untrusted third party (TP). Compared with existing M-SQKD protocols, our protocol significantly reduces the overall quantum burden and improves the qubit efficiency, where TP only needs to prepare and measure qubits in the X basis and two lightweight participants are just required to execute three unitary operations and reflect qubits. Furthermore, the detailed security analysis verifies that the proposed protocol can against three well-known attacks.
Abstract Semi‐quantum key distribution is a very interesting new branch of quantum key distribution. It can be implemented when one or more participants are restricted to operate quantum states only on the quantum computational basis. Very recently, a mediated semi‐quantum key distribution protocol without invoking two participants' quantum measurement has been proposed. The protocol allows two “classical” participants without sophisticated quantum capability to establish a shared secret key under an untrusted third party. It is claimed that the protocol is secure against several well‐known attacks. However, in this paper, it is first pointed out that there exist three attacks “Measurement Attack, Modification Attack, and Collective Attack” on the mediated semi‐quantum key distribution protocol without invoking quantum measurement. By proposed attacks, a malicious third party can obtain the secret key without being noticed by legitimated participants.