Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Laser Physics Letters

A novel semiquantum key distribution protocol with Bell states

Zhenying Sun

Published Jul 19, 2024• 4 citations
Publisher

Abstract

Abstract In this paper, a novel semiquantum key distribution (SQKD) protocol is proposed by using Bell state, where quantum Alice can sharesecret bits with classical Bob via quantum channel. Classical Bob is required to measure particles with thebasis, produce fresh particles within thebasis and send particles via quantum channel. Security analysis turns out that this protocol is immune to various attacks launched by the outside eavesdropper. Compared with present SQKD protocols using Bell states without a third party, on one hand, this protocol has the highest qubit efficiency; and on the other hand, the reflecting operations of the classical user in this protocol contribute to the generation of final shared key.

DOI
10.1088/1612-202x/ad59fe

Related papers

Semi-quantum key distribution with two classical users

Wan Qing Wu, Chen Yang Sun

Semi-quantum key distribution (SQKD) is an important research issue which allows one quantum participant equipped with advanced quantum devices to distribute a shared secret key securely with one classical user who has restricted capabilities. In this paper, we propose a SQKD protocol which allows one quantum user to distribute two different private secret keys to two classical users respectively at the same time. Alice distributes two particle sequences from Bell states to Bob and Charlie respectively. Once the particles have been processed and returned, Alice can simultaneously detect reflected particles by Bob and Charlie based on Bell-state measurement and generate two different raw keys. To enable more participants in sharing keys, this protocol can be extended to the m + 1 party communication scheme by employing m-particle GHZ state. In large-scale communication networks, this extended model significantly reduces the complexity of communication compared to the traditional SQKD scheme. Security analyses show that the presented protocol is free from several general attacks, such as the entangle-measure attack, the modification attack, the double CNOT attack, and so on.

Frontiers in Physics•Oct 20, 2022•3 citations

Security improvement for a novel semiquantum key distribution protocol with Bell states

W.P. Tan, Xiangfu Zou, Xinting Su +1 more

Abstract Semiquantum key distribution (SQKD) facilitates the establishment of secure keys even when one user (designated as the classical user) is constrained to performing quantum state preparation and measurement only within a fixed computational basis. From a resource-theoretic perspective, this approach presents both novelty and theoretical significance. Recently, a novel SQKD protocol based on Bell states, where the classical user’s REFLECT operations directly contribute to the generation of the final shared key was proposed [ Laser Physics Letters , 21 (9):095201, 2024]. However, our analysis reveals that this protocol is vulnerable to double CNOT attacks, posing security risks. To address this, we propose an improved SQKD protocol that maintains resistance to double CNOT attacks while preserving the classical user’s REFLECT operations as a functional component for key generation. Notably, we rigorously prove the unconditional security of the improved protocol and derive a maximum allowable error rate of 8.92% in depolarizing channels. This work serves two purposes: (1) it alerts SQKD protocol designers to the identified security vulnerability, and (2) it provides a foundational reference for establishing unconditional security proofs in SQKD protocols where REFLECT operations contribute to key generation.

Physica Scripta•Nov 1, 2025•2 citations

Semiquantum Key Distribution Using Entangled States

Jian Wang, Sheng Zhang, Quan Zhang +1 more

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 semi-quantum 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.

arXiv:1104.1267•Chinese Physics Letters•Oct 1, 2011•100 citations

Experimentally feasible protocol for semiquantum key distribution

Michel Boyer, Matty Katz, Rotem Liss +1 more

Quantum key distribution (QKD) protocols make it possible for two quantum parties to generate a secret shared key. Semiquantum key distribution (SQKD) protocols, such as ``QKD with classical Bob'' and ``QKD with classical Alice'' (that have both been proven robust), achieve this goal even if one of the parties is classical. However, existing SQKD protocols are not experimentally feasible with current technology. Here we suggest a protocol, ``Classical Alice with a controllable mirror,'' that can be experimentally implemented with current technology (using four-level systems instead of qubits), and we prove it to be robust.

arXiv:1701.07044•Physical Review A•Dec 29, 2017•73 citations

Semiquantum key distribution with high quantum noise tolerance

Omar Amer, Walter O. Krawec

Semiquantum key distribution protocols are designed to allow two parties to establish a shared secret key, secure against an all-powerful adversary, even when one of the users is restricted to measuring and preparing quantum states in one single basis. While interesting from a theoretical standpoint, these protocols have the disadvantage that a two-way quantum communication channel is necessary which generally limits their theoretical efficiency and noise tolerance. In this paper, we construct a semiquantum key distribution (SQKD) protocol which actually takes advantage of this necessary two-way channel, and, after performing an information theoretic security analysis against collective attacks, we show it is able to tolerate a channel noise level higher than any prior SQKD protocol to date. We also compare the noise tolerance of our protocol to other two-way fully quantum protocols, along with BB84 with classical advantage distillation. We also comment on some practical issues involving semiquantum key distribution (in particular, concerning the potential complexity in physical implementation of our protocol as compared with other standard QKD protocols). Finally, we develop techniques that can be applied to the security analysis of other (S)QKD protocols reliant on a two-way quantum communication channel.

arXiv:1812.04144•Physical Review A•Aug 16, 2019•33 citations

High-Dimensional Semiquantum Cryptography

Hasan Iqbal, Walter O. Krawec

A semiquantum key distribution (SQKD) protocol allows two users, one of whom is restricted in their quantum capabilities to being nearly classical, to establish a shared secret key, secure against an all-powerful adversary. The study of such protocols helps to answer the fundamental question of “how quantum” must a protocol be to gain an advantage over classical communication. In this article, we design a new SQKD protocol using high-dimensional quantum states and conduct an information theoretic security analysis. We show that, similar to the fully quantum key distribution case, high-dimensional systems can increase the noise tolerance in the semiquantum case. Furthermore, we prove several general security results which are applicable to other (S)QKD protocols (both high-dimensional ones and standard qubit-based protocols) utilizing a two-way quantum channel.

arXiv:1907.11340•IEEE Transactions on Quantum Engineering•Jan 1, 2020•30 citations
Abstract In this paper, a novel semiquantum key distribution (SQKD) protocol is proposed by using Bell state, where quantum Alice can sharesecret bits with classical Bob via quantum channel. Classical Bob is required to measure particles with thebasis, produce fresh particles within thebasis and send particles via quantum channel. Security analysis turns out that this protocol is immune to various attacks launched by the outside eavesdropper. Compared with present SQKD protocols using Bell states without a third party, on one hand, this protocol has the highest qubit efficiency; and on the other hand, the reflecting operations of the classical user in this protocol contribute to the generation of final shared key.
Semi-quantum key distribution (SQKD) is an important research issue which allows one quantum participant equipped with advanced quantum devices to distribute a shared secret key securely with one classical user who has restricted capabilities. In this paper, we propose a SQKD protocol which allows one quantum user to distribute two different private secret keys to two classical users respectively at the same time. Alice distributes two particle sequences from Bell states to Bob and Charlie respectively. Once the particles have been processed and returned, Alice can simultaneously detect reflected particles by Bob and Charlie based on Bell-state measurement and generate two different raw keys. To enable more participants in sharing keys, this protocol can be extended to the m + 1 party communication scheme by employing m-particle GHZ state. In large-scale communication networks, this extended model significantly reduces the complexity of communication compared to the traditional SQKD scheme. Security analyses show that the presented protocol is free from several general attacks, such as the entangle-measure attack, the modification attack, the double CNOT attack, and so on.
Abstract Semiquantum key distribution (SQKD) facilitates the establishment of secure keys even when one user (designated as the classical user) is constrained to performing quantum state preparation and measurement only within a fixed computational basis. From a resource-theoretic perspective, this approach presents both novelty and theoretical significance. Recently, a novel SQKD protocol based on Bell states, where the classical user’s REFLECT operations directly contribute to the generation of the final shared key was proposed [ Laser Physics Letters , 21 (9):095201, 2024]. However, our analysis reveals that this protocol is vulnerable to double CNOT attacks, posing security risks. To address this, we propose an improved SQKD protocol that maintains resistance to double CNOT attacks while preserving the classical user’s REFLECT operations as a functional component for key generation. Notably, we rigorously prove the unconditional security of the improved protocol and derive a maximum allowable error rate of 8.92% in depolarizing channels. This work serves two purposes: (1) it alerts SQKD protocol designers to the identified security vulnerability, and (2) it provides a foundational reference for establishing unconditional security proofs in SQKD protocols where REFLECT operations contribute to key generation.
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 semi-quantum 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.
Quantum key distribution (QKD) protocols make it possible for two quantum parties to generate a secret shared key. Semiquantum key distribution (SQKD) protocols, such as ``QKD with classical Bob'' and ``QKD with classical Alice'' (that have both been proven robust), achieve this goal even if one of the parties is classical. However, existing SQKD protocols are not experimentally feasible with current technology. Here we suggest a protocol, ``Classical Alice with a controllable mirror,'' that can be experimentally implemented with current technology (using four-level systems instead of qubits), and we prove it to be robust.
Semiquantum key distribution protocols are designed to allow two parties to establish a shared secret key, secure against an all-powerful adversary, even when one of the users is restricted to measuring and preparing quantum states in one single basis. While interesting from a theoretical standpoint, these protocols have the disadvantage that a two-way quantum communication channel is necessary which generally limits their theoretical efficiency and noise tolerance. In this paper, we construct a semiquantum key distribution (SQKD) protocol which actually takes advantage of this necessary two-way channel, and, after performing an information theoretic security analysis against collective attacks, we show it is able to tolerate a channel noise level higher than any prior SQKD protocol to date. We also compare the noise tolerance of our protocol to other two-way fully quantum protocols, along with BB84 with classical advantage distillation. We also comment on some practical issues involving semiquantum key distribution (in particular, concerning the potential complexity in physical implementation of our protocol as compared with other standard QKD protocols). Finally, we develop techniques that can be applied to the security analysis of other (S)QKD protocols reliant on a two-way quantum communication channel.
A semiquantum key distribution (SQKD) protocol allows two users, one of whom is restricted in their quantum capabilities to being nearly classical, to establish a shared secret key, secure against an all-powerful adversary. The study of such protocols helps to answer the fundamental question of “how quantum” must a protocol be to gain an advantage over classical communication. In this article, we design a new SQKD protocol using high-dimensional quantum states and conduct an information theoretic security analysis. We show that, similar to the fully quantum key distribution case, high-dimensional systems can increase the noise tolerance in the semiquantum case. Furthermore, we prove several general security results which are applicable to other (S)QKD protocols (both high-dimensional ones and standard qubit-based protocols) utilizing a two-way quantum channel.