Quantum secret sharing (QSS) is a typical multipartite quantum cryptographic primitive. Although QSS is theoretically secure, imperfect experimental devices would threaten its security. The glare blinding attack is a strong attack against practical single-photon detectors. In the paper, we propose a simple and effective glare blinding attack strategy in the practical three-partite QSS system. The glare blinding attack combined with the fake-state attack enables the eavesdropper to steal parts of transmitted keys without being detected. We provide the numerical simulation of QSS's performance in the above attack condition. The simulation results show that QSS's maximal photon transmission distance is largely reduced to about 10 km. Our work indicates the importance of inspecting QSS's security loopholes in the detector. The glare blinding attack should become a general testing item in the security evaluation standard of QSS.
Quantum secret sharing (QSS) is a typical multipartite quantum cryptographic primitive. Although QSS is theoretically secure, imperfect experimental devices would threaten its security. The glare blinding attack is a strong attack against practical single-photon detectors. In the paper, we propose a simple and effective glare blinding attack strategy in the practical three-partite QSS system. The glare blinding attack combined with the fake-state attack enables the eavesdropper to steal parts of transmitted keys without being detected. We provide the numerical simulation of QSS's performance in the above attack condition. The simulation results show that QSS's maximal photon transmission distance is largely reduced to about 10 km. Our work indicates the importance of inspecting QSS's security loopholes in the detector. The glare blinding attack should become a general testing item in the security evaluation standard of QSS.
Measurement-device-independent entanglement witness (MDI-EW) plays an important role for detecting entanglement with untrusted measurement device. We present a double blinding-attack on a quantum secret sharing (QSS) protocol based on GHZ state. Using the MDI-EW method, we propose a QSS protocol against all detector side-channels. We allow source flaws in practical QSS system, so that Charlie can securely distribute a key between the two agents Alice and Bob over long distances. Our protocol provides condition on the extracted key rate for the secret against both external eavesdropper and arbitrary dishonest participants. A tight bound for collective attacks can provide good bounds on the practical QSS with source flaws. Then we show through numerical simulations that using single-photon source a secure QSS over 136 km can be achieved.
We present a fake-signal-and-cheating attack strategy for the dishonest agent in quantum secret sharing (QSS) to steal the information of the other agents' fully and freely. It is found that almost all the QSS protocols existing, such as the two famous QSS protocols, the Hillery-Buzˇek-Berthiaume [Phys. Rev. A \textbf{59}, 1829 (1999)] and the Karlsson-Koashi-Imoto [Phys. Rev. A \textbf{59}, 162 (1999)], can be eavesdropped freely if the process for the eavesdropping check is accomplished with the cooperation of the dishonest agent. He can sends a fake signal to the other agents after intercepting the original photons and storing them. His action can be hidden with entanglement swapping and cheating when the photons are chosen as the samples for checking eavesdropping. Finally, we present a possible improvement of these QSS protocols' security with decoy photons.
Abstract Quantum key distribution (QKD), rooted in quantum mechanics, offers information-theoretic security. However, practical systems open security threats due to imperfections, notably bright-light blinding attacks targeting single-photon detectors. Here, we propose a concise, robust defense strategy for protecting single-photon detectors in QKD systems against blinding attacks. Our strategy uses a dual approach: detecting the bias current of the avalanche photodiode (APD) to defend against continuous-wave blinding attacks, and monitoring the avalanche amplitude to protect against pulsed blinding attacks. By integrating these two branches, the proposed solution effectively identifies and mitigates a wide range of bright light injection attempts, significantly enhancing the resilience of QKD systems against various bright-light blinding attacks. This method fortifies the safeguards of quantum communications and offers a crucial contribution to the field of quantum information security.
Recently, Gao et al.'s [ Commun. Theor. Phys. 52 (2009) 421 ] multiparty quantum secret sharing (MQSS) protocol with two-photon three-dimensional Bell states was enhanced by Hwang et al. [ Commun. Theor. Phys. 56 (2011) 79 ]. The improved protocol removes some unnecessary unitary operations, devices, and transmissions by the technique of decoy single photons and careful modification. However, in this paper, we investigate the security of the improved protocol and find it is insecure. The eavesdropper can steal all Alice's secret information. Furthermore, a feasible modification to remedy the security loophole is put forward. Our improved protocol provides a basic method to modify a kind of MQSS protocols which cannot resist the collusion attack.
It is generally believed that nonorthogonal operations which can realize the state transformation between two nonorthogonal bases may ensure the security of many quantum communication protocols. However, in this paper, we present a powerful attack against quantum secret sharing protocols of these kinds. Applying entangled photons as fake signals, Eve can successfully steal the exact information without being revealed. We also give our effective modification to improve it. Under the suggested checking strategy, even to Eve's most general attack, it is robust and secure.
Abstract In the field of quantum cryptography, Quantum Secret Sharing (QSS) holds substantial importance, with identity authentication emerging as a key strategy for safeguarding information. It efficiently certifies the identification of both persons involved in the conversation, which contributes to increased security measures. Our proposal, a (m, n) threshold Quantum Secret Sharing (QSS) scheme introduces a unique approach to mutual identity authentication, utilizing mutually unbiased bases. During the secret recovery phase, the scheme ensures that secrets exclusively held by participants remain undisclosed and are not transmitted, reinforcing the security of the communication process. As a result, external eavesdroppers are left empty-handed in their attempt to access information about secrets during this phase. Our protocol surpasses in terms of security, effectiveness, and practicality, proving its resilience against intercept–resend attacks, collusion attacks, collective attacks, and forgery attacks according to a comprehensive security analysis.