Lightweight mediated semi-quantum key distribution protocol

2019 ◽  
Vol 34 (34) ◽  
pp. 1950281 ◽  
Author(s):  
Chia-Wei Tsai ◽  
Chun-Wei Yang ◽  
Narn-Yih Lee

Classical users can share a secret key with a quantum user by using a semi-quantum key distribution (SQKD) protocol. Allowing two classical users to share a secret key is the objective of the mediated semi-quantum key distribution (MSQKD) protocol. However, the existing MSQKD protocols need a quantum user to assist two classical users in distributing the secret keys, and these protocols require that the classical users be equipped with a Trojan horse photon detector. This reduces the practicability of the MSQKD protocols. Therefore, in this study we propose a lightweight MSQKD, in which the two participants and third party are classical users. Due to the usage of the one-way transmission strategy, the proposed lightweight MSQKD protocol is free from quantum Trojan horse attack. The proposed MSQKD is more practical than the existing MSQKD protocols.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chia-Wei Tsai ◽  
Chun-Wei Yang

AbstractThe 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.


2015 ◽  
Vol 15 (15&16) ◽  
pp. 1295-1306
Author(s):  
Zoe Amblard ◽  
Francois Arnault

The Ekert quantum key distribution protocol [1] uses pairs of entangled qubits and performs checks based on a Bell inequality to detect eavesdropping. The 3DEB protocol [2] uses instead pairs of entangled qutrits to achieve better noise resistance than the Ekert protocol. It performs checks based on a Bell inequality for qutrits named CHSH-3 and found in [3, 4]. In this paper, we present a new protocol, which also uses pairs of entangled qutrits, but gaining advantage of a Bell inequality which achieves better noise resistance than the one used in 3DEB. The latter inequality is called here hCHSH-3 and was discovered in [5]. For each party, the hCHSH-3 inequality involves four observables already used in CHSH-3 but also two products of observables which do not commute. We explain how the parties can measure the observables corresponding to these products and thus are able to check the violation of hCHSH-3. In the presence of noise, this violation guarantees the security against a local Trojan horse attack. We also designed a version of our protocol which is secure against individual attacks.


2012 ◽  
Vol 10 (05) ◽  
pp. 1250059 ◽  
Author(s):  
MAOZHU SUN ◽  
XIANG PENG ◽  
YUJIE SHEN ◽  
HONG GUO

The original two-way continuous-variable quantum-key-distribution (CV-QKD) protocols [S. Pirandola, S. Mancini, S. Lloyd and S. L. Braunstein, Nat. Phys. 4 (2008) 726] give the security against the collective attack on the condition of the tomography of the quantum channels. We propose a family of new two-way CV-QKD protocols and prove their security against collective entangling cloner attacks without the tomography of the quantum channels. The simulation result indicates that the new protocols maintain the same advantage as the original two-way protocols whose tolerable excess noise surpasses that of the one-way CV-QKD protocol. We also show that all sub-protocols within the family have higher secret key rate and much longer transmission distance than the one-way CV-QKD protocol for the noisy channel.


2005 ◽  
Vol 03 (supp01) ◽  
pp. 75-86
Author(s):  
MASATO KOASHI

In the BB84 protocol with a perfect single photon source, the key rate decreases linearly with the transmission η of the channel. If we simply replace this source with a weak coherent-state pulse, the key rate drops more rapidly (as O(η2)) since the presence of multiple photons favors the eavesdropper. Here we discuss the unconditional security of a quantum key distribution protocol in which bit values are encoded in the phase of a weak coherent-state pulse relative to a strong reference pulse, which is essentially the one proposed by Bennett in 1992 (the B92 scheme). We show that in the limit of high loss in the transmission channel, we can construct a secret key with a rate proportional to the transmission η of the channel.


Entropy ◽  
2021 ◽  
Vol 23 (12) ◽  
pp. 1691
Author(s):  
Fan Jing ◽  
Weiqi Liu ◽  
Lingzhi Kong ◽  
Chen He

In the continuous variable measurement-device-independent quantum key distribution (CV-MDI-QKD) protocol, both Alice and Bob send quantum states to an untrusted third party, Charlie, for detection through the quantum channel. In this paper, we mainly study the performance of the CV-MDI-QKD system using the noiseless linear amplifier (NLA). The NLA is added to the output of the detector at Charlie’s side. The research results show that NLA can increase the communication distance and secret key rate of the CV-MDI-QKD protocol. Moreover, we find that the more powerful the improvement of the performance with the longer gain of NLA and the optimum gain is given under different conditions.


2021 ◽  
Author(s):  
Qiang Zhang ◽  
Wen-Zhao Liu ◽  
Yu-Zhe Zhang ◽  
Yi-Zheng Zhen ◽  
Ming-Han Li ◽  
...  

Abstract The security of quantum key distribution (QKD) usually relies on that the users’s devices are well characterized according to the security models made in the security proofs. In contrast,device-independent QKD an entanglement-based protocol permits the security even without any knowledge of the underlying devices. Despite its beauty in theory, device-independent QKD is elusive to realize with current technology. This is because a faithful realization requires ahigh-quality violation of Bell inequality without the fair-sampling assumption. Particularly, in a photonic realization, a rather high detection efficiency is needed where the threshold values depend on the security proofs; this efficiency is far beyond the current reach. Here, both theoretical and experimental innovations yield the realization of device-independent QKD based on a photonic setup. On the theory side, to relax the threshold efficiency for practical deviceindependent QKD, we exploit the random post-selection combined with adding noise for preprocessing, and compute the entropy with complete nonlocal correlations. On the experiment side, we develop a high-quality polarization-entangled photonic source and achieve state-of-theart (heralded) detection efficiency of 87.49%, which outperforms previous experiments and satisfies the threshold efficiency for the first time. Together, we demonstrate device-independent QKD at a secret key rate of 466 bits/s over 20 m standard fiber in the asymptotic limit against collective attacks. Besides, we show the feasibility of generating secret keys at a fiber length of 220 meters. Importantly, our photonic implementation can generate entangled photons at a high rate and in the telecom wavelength, which is desirable for high-speed key generation over long distances. The results not only prove the feasibility of device-independent QKD with realistic devices, but also push the security of communication to an unprecedented level.


2019 ◽  
Author(s):  
Meiying Cui ◽  
Yixin Zhang

AbstractDNA has become a promising candidate as future data storage medium, which makes DNA steganography indispensable in DNA data security. While PCR primers are conventional secret keys in DNA steganography, the information can be read once the primers are intercepted. New steganography approach is needed to make the DNA-encoded information safer, if not unhackable. Herein, by mixing information-carrying DNA with partially degenerated DNA library containing single or multiple restriction sites, we build an additional protective layer, which can be removed by desired restriction enzymes as secondary secret keys. As PCR is inevitable for reading DNA-encrypted information, heating will cause reshuffling and generate endonuclease-resistant mismatched duplexes, especially for DNA with high sequence diversity. Consequently, with the incorporation of randomness, the DNA steganography possesses both quantum key distribution (QKD)-like function for detecting PCR by an interceptor and self-destructive property. With a DNA-ink incorporating the steganography, the authenticity of a writing can be confirmed only by authorized person with the knowledge of all embedded keys.


2020 ◽  
Vol 10 (21) ◽  
pp. 7788
Author(s):  
Yaxi Pan ◽  
Ling Zhang ◽  
Duan Huang

As the existence of non-zero reflection coefficients in the real component of continuous-variable quantum key distribution (CV-QKD) systems, Eve can probe the system by sending the bright light pulses into Alice’s set-up. With the analysis of back-reflections, Eve only takes a few back-reflected photons to intercept information and obtain the raw key bit. In this paper, the attack problems are converted into the information leakage problems. First, we analyzed the Trojan horse attacks with different wavelengths and confirmed its side effects, such as crosstalk and anti-Stokes Raman scattering, by a numerical simulation. Then, based on the wavelength-dependent property of beam splitter, we presented a practical way to estimate the deviation of shot noise and therefore correct the excess noise by inserting different wavelength pulses under joint attacks. Finally, we specified the security bounds of the system through quantifying the excess noise bounds caused by the Trojan horse attacks and provided a theoretical reference for the secret key transmission of system. As a consequence, the transmission errors within the security bounds can be negligible and the legitimate users will not perceive the presence of Eve.


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