Quantum Key Distribution (QKD) is an enabling technology to current modern cryptography which utilizes nature properties of light to transfer key information safely over an unsecured channel. Via this application, both communicating parties can share an identical secret key for their chosen cryptographic scheme in various applications which demand a protection to their highly important message. A designated key bits reconciliation method is known as QKD protocol. The first ever protocol introduced and popularly used is the Bennett and Brassard 1984 (BB84) protocol. However the implementation with current technology has restricted its primary capability to guarantee the security of secret key establishment. As a result, it is vulnerable to Eavesdropping attack. This leads many works on practical protocol and the most significant contribution having used the same setup as the BB84 protocol is the Scarani, Acin, Ribordy and Gisin 2004 (SARG04) protocol. The SARG04 is more robust against photon number splitting attacks and double the BB84 critical transmission distance. Nevertheless SARG04 protocol still has lower percentage of sifted key bit compared to BB84 protocol. Therefore this study has embarked its objectives on identifying and proposing a new QKD protocol which can improve the robustness while allowing higher final key length. The alternative protocol is designed by combining the existing SARG04 decoding with improved SARG04 decoding (ISARG04). Unlike SARG04 which discards any inconclusive result from his measurement, ISARG04 will always accept the non orthogonal state with half probability of error. The robustness of the proposed protocol is simulated based on simple Intercept Resend attack and photon number splitting attacks in quantum key distribution. This new protocol is robust up to two photons per pulse and has an improvement to secure transmissions of bits at higher link loss, up to 26.7 dB. In summary, this work has presented an improved discrete variable protocol which improved the sifted key length and robust to eavesdropping. It is hope that, this contribution might be a breakthrough for near future QKD protocol.
Quantum Key Distribution (QKD) is an enabling technology to current modern cryptography which utilizes nature properties of light to transfer key information safely over an unsecured channel. Via this application, both communicating parties can share an identical secret key for their chosen cryptographic scheme in various applications which demand a protection to their highly important message. A designated key bits reconciliation method is known as QKD protocol. The first ever protocol introduced and popularly used is the Bennett and Brassard 1984 (BB84) protocol. However the implementation with current technology has restricted its primary capability to guarantee the security of secret key establishment. As a result, it is vulnerable to Eavesdropping attack. This leads many works on practical protocol and the most significant contribution having used the same setup as the BB84 protocol is the Scarani, Acin, Ribordy and Gisin 2004 (SARG04) protocol. The SARG04 is more robust against photon number splitting attacks and double the BB84 critical transmission distance. Nevertheless SARG04 protocol still has lower percentage of sifted key bit compared to BB84 protocol. Therefore this study has embarked its objectives on identifying and proposing a new QKD protocol which can improve the robustness while allowing higher final key length. The alternative protocol is designed by combining the existing SARG04 decoding with improved SARG04 decoding (ISARG04). Unlike SARG04 which discards any inconclusive result from his measurement, ISARG04 will always accept the non orthogonal state with half probability of error. The robustness of the proposed protocol is simulated based on simple Intercept Resend attack and photon number splitting attacks in quantum key distribution. This new protocol is robust up to two photons per pulse and has an improvement to secure transmissions of bits at higher link loss, up to 26.7 dB. In summary, this work has presented an improved discrete variable protocol which improved the sifted key length and robust to eavesdropping. It is hope that, this contribution might be a breakthrough for near future QKD protocol.
Quantum Key Distribution (QKD) can be considered as the best secured technol- ogy that appreciates the quantum mechanics principals in terms of information transmission over vulnerable quantum channel. QKD ensures that both parties can share the matched secret key through particular designated method in order to protect the shared key from the intruders to eavesdrop the information. Every procedure needs its own protocol to carry out the work accordingly and there are many QKD protocols in the quantum system that can be used in the transmission. In this study, the Scarani, Acin, Ribordy and Gisin 2004 (SARG04) protocol has been choosen because of its robustness against Photon Number Split- ting (PNS) attack compared to Bennet and Brassard 1984 (BB84) protocol. It is more likely that by improving secret key rate, the system can be more robust. Therefore, enhancing the secret key rate is one of the best way to enhance the security and authentication of the communication system. The Improved SARG04 (ISARG04) was introduced in a thesis by Ghazali (2012) in order to enhance secret key rate and its confidentiality from unauthorized parties. However, the studies were not being compared with SARG04 preprocessing technique. Therefore in this study, a mathematical modeling and a comparison between the secret key rate of the preprocessing of the existing SARG04 and the proposed technique of ISARG04 will be investigated in more details.The results of this study show that the preprocessing technique of ISARG04 pro- tocol is robust within the range of Quantum Bit Error Rate (QBER) between 0:14625 and 0:14880. The ratio of secret key rate between ISARG04 and SARG04 is exceeds one, hence the modification is improved. This outcome has shown an improved secret key rate against PNS attack. In consequence, it is expected that this study will bring an aspiration and contribution for future QKD protocol.
Quantum Key Distribution is a leading-edge cryptographic technology that influences the fundamentals of physics quantum mechanics to enable the secure exchange of encryption keys, establishing peerless levels of confidentiality and aversion against eavesdropping. Quantum Key Distribution (QKD) protocols have been hinged on proceeding in the field of quantum cryptography, guaranteeing safer communication in the existence of adversaries. This paper lays out the comparative survey of some important QKD protocols which are BB84, E91, TF, CV, MDI, COW DPS and SARG04. Each protocol has its unique advantages, characteristics, and limitations, making them appropriate for their different deployment environmental areas. BB84 works on the principle of polarization state and E91 works on entanglement. Both are good at providing robust security under various attack models. To overcome the distance limitations of traditional QKD protocols Twin-Field protocol is a way better that attain more advanced performance in long-distance communication. In Continuous Variable QKD, the requirement of detectors turns out to be lower at the practical levels. Trusted detectors are abolished in MDI-QKD, intensifying the security against the detector side-channel attacks. Coherent One-Way QKD powers up the key rates by employing the encoding in time-bin and phase coherence. Differential Phase Shift-QKD targeted on differential phase shifts for providing robustness against definite types of attack. Finally, Photon number splitting (PNS) attacks get resistance from the SARG04 QKD protocol making it more secure way in a practical framework. In this paper, we compare the performances of these protocols in terms of key rates, error tolerance, security, implementation challenges, advantages, limitations, and feasibility in the real world that are offering perception into their capability for future quantum communication networks.
Quantum Key Distribution (QKD) is a technique that enables secure communication between two parties by sharing a secret key. One of the most well-known QKD protocols is the BB84 protocol, proposed by Charles Bennett and Gilles Brassard in 1984. In this protocol, Alice and Bob use a quantum channel to exchange qubits, allowing them to generate a shared key that is resistant to eavesdropping. This paper presents a comparative study of existing QKD schemes, including the BB84 protocol, and highlights the advancements made in the BB84 protocol over the years. The study aims to provide a comprehensive overview of the different QKD schemes and their strengths and weaknesses and demonstrate QKDs working principles through existing simulations and implementations. Through this study, we show that the BB84 protocol is a highly secure QKD scheme that has been extensively studied and implemented in various settings. Furthermore, we discuss the improvements made to the BB84 protocol to enhance its security and practicality, including the use of decoy states and advanced error correction techniques. Overall, this paper provides a comprehensive analysis of QKD schemes, focusing on the BB84 protocol in secure communication technologies.
We compare the performance of Bennett-Brassard 1984 (BB84) and Scarani-Acin-Ribordy-Gisin 2004 (SARG04) protocols, the latter of which was proposed by V. Scarani et al. [Phys. Rev. Lett. 92, 057901 (2004)]. Specifically, in this paper, we investigate the SARG04 protocol with two-way classical communications and the SARG04 protocol with decoy states. In the first part of the paper, we show that the SARG04 scheme with two-way communications can tolerate a higher bit error rate (19.4% for a one-photon source and 6.56% for a two-photon source) than the SARG04 one with one-way communications (10.95% for a one-photon source and 2.71% for a two-photon source). Also, the upper bounds on the bit error rate for the SARG04 protocol with two-way communications are computed in a closed form by considering an individual attack based on a general measurement. In the second part of the paper, we propose employing the idea of decoy states in the SARG04 scheme to obtain unconditional security even when realistic devices are used. We compare the performance of the SARG04 protocol with decoy states and the BB84 one with decoy states. We find that the optimal mean-photon number for the SARG04 scheme is higher than that of the BB84 one when the bit error rate is small. Also, we observe that the SARG04 protocol does not achieve a longer secure distance and a higher key generation rate than the BB84 one, assuming a typical experimental parameter set.
Abstract Quantum key distribution (QKD) offers information‐theoretic security by leveraging the principles of quantum mechanics. This means the security is independent of all future advances in algorithm or computational power. However, due to the non‐availability of single‐photon sources, most traditional QKD protocols are vulnerable to various attacks, such as photon number‐splitting (PNS) attacks. Also, the imperfections in the measuring devices open a loophole for side channels that an eavesdropper may exploit to launch attacks such as large‐pulse attacks. As a result, this compromises the security of transmitted information. To address these challenges, the authors present a QKD protocol that is secure against both large‐pulse attacks and PNS attacks at zero‐error, in which the eavesdropper does not introduce any error, but still, the legitimate users of the system cannot distil a secure key. A notable feature of the proposed protocol is that it promotes greater robustness against both attacks than the Bennett‐Brassard 1984 (BB84) protocol or the Scarani‐Acin‐Ribordy‐Gisin 2004 (SARG04) protocol.
Quantum communication leverages the principles of quantum mechanics, such as superposition and entanglement, for inherently secure data transmission that can detect any eavesdropping attempt. This research addresses the limitations of classical encryption by proposing a hybrid Quantum Key Distribution (QKD) protocol that integrates the Bennett & Brassard 1984 Protocol(BB84) and Scarani-Acín-Ribordy-Gisin 2004 Protocol(SARG04) protocols. The primary objective is to enhance resilience against advanced threats such as Photon Number Splitting (PNS) and collective attacks, which are significant vulnerabilities in standard QKD implementations. The quantum channel is modeled using Qiskit Aer's noise framework, incorporating fiber attenuation (0.1−0.25dB/km), depolarization (1−5%), and detector dark counts (0.01−0.03probability), varied across 10 rounds. A simulation spanning 10 rounds evaluated key metrics, including Quantum Bit Error Rate (QBER), photon loss, and final key entropy. The results demonstrate the protocol's robustness, achieving a 0 % QBER in 50 % of the trials, representing a significant improvement in secure key generation. The average QBER across all rounds was 12.5 %, which is well below the 11 % theoretical threshold for secure communication. The highest QBER recorded was5 0 %in Round 02, where high depolarization and an eavesdropping attempt were simulated. The work's findings indicate that the hybrid BB84-SARG04 protocol significantly enhances the security and reliability of quantum communication.