This paper introduces a modified quantum key distribution (QKD) protocol based on card-shuffling, designed to enhance security against eavesdropper photon number splitting (PNS) strategies. The proposed technique accommodates light pulses with few photons, substantially augmenting the effectiveness and reliability of QKD. It can be implemented as multi-photon-lane systems, enabling concurrent key distribution to multiple users or amalgamation of key data to amplify individual use r key rates. The study assesses the proposed technique utilizing three well-established polarization-encrypted QKD protocols, BB84, B92, and SSP99, and simulations utilizing 4-photon lane systems with wavelengths of 800 nm, 1300 nm, and 1550 nm. The findings, encompassing correlations such as useful key rate, maximum key distribution distance, quantum bit error rate, and photon number probability, are analyzed and compared under different conditions. The outcomes reveal that combining the technique with BB84-based systems employing 1300 nm light pulses and a photon number probability of 1.0 attains a maximum QKD effectiveness of 12.34 Gbit-km/s. Moreover, the effectiveness can be increased to 49.36 Gbit-km/s by implementing the proposed 4-photon-lane system as the serial key-combining scheme. The potential of using multi-photon-lane implementations alongside the proposed technique to enhance the effectiveness and reliability of QKD is theoretically investigated and discussed.
This paper introduces a modified quantum key distribution (QKD) protocol based on card-shuffling, designed to enhance security against eavesdropper photon number splitting (PNS) strategies. The proposed technique accommodates light pulses with few photons, substantially augmenting the effectiveness and reliability of QKD. It can be implemented as multi-photon-lane systems, enabling concurrent key distribution to multiple users or amalgamation of key data to amplify individual use r key rates. The study assesses the proposed technique utilizing three well-established polarization-encrypted QKD protocols, BB84, B92, and SSP99, and simulations utilizing 4-photon lane systems with wavelengths of 800 nm, 1300 nm, and 1550 nm. The findings, encompassing correlations such as useful key rate, maximum key distribution distance, quantum bit error rate, and photon number probability, are analyzed and compared under different conditions. The outcomes reveal that combining the technique with BB84-based systems employing 1300 nm light pulses and a photon number probability of 1.0 attains a maximum QKD effectiveness of 12.34 Gbit-km/s. Moreover, the effectiveness can be increased to 49.36 Gbit-km/s by implementing the proposed 4-photon-lane system as the serial key-combining scheme. The potential of using multi-photon-lane implementations alongside the proposed technique to enhance the effectiveness and reliability of QKD is theoretically investigated and discussed.
This paper presents a modified quantum key distribution (QKD) protocol with its advantage ability to against the photon number splitting (PNS) strategy. As a result of the proposed protocol with the specified parameters of k = 1024 bits, y = 10 bits, and the round repeating of n = 10, the eavesdropper can achieve the correct information with a probability of only 1.97×10-31. Moreover, the proposed protocol allows each the photon pulse can consist of a few of photons, which is valuable to the maximize photon number of μ=1 and resulting in a significant higher useful bit rate. From the simulation results, the obtained useful bits rates for each the photon pulse of 800 nm, 1300 nm, and 1550 nm, are approximately of 242.2 kbit/s, 7.4 Mbit/s, and 119.8 kBit/s, can be achieved at the distances of 20 km, 60 km, and 120 km, respectively. The QKD system parameters for each the considered wavelength are specified as: the photon pulses rate of 1 GHz and 10 GHz, the photon number of μ=0.1 and 1.0, The attenuations of 2.0, 0.35, and 0.25 dB/km, the detector efficiencies of 50%, 20%, and 10%, with the dark count probabilities of 10-7, 10-5, and 10-5, respectively. The potential of using such the proposed protocol with a double layers QKD system is performed and discussed.
In the last ten years, quantum computing has made substantial progress, presenting a strong challenge to traditional encryption methods that depend on solving discrete algorithmic problems. With the advent of the quantum era, conventional encryption methods are becoming more susceptible to attacks. This paper investigates possible attacks that exploit vulnerabilities in quantum cryptography, specifically investigating weaknesses in quantum key distribution (QKD) systems. The text thoroughly explores advanced attack strategies of photon number splitting highlight the existing vulnerabilities. The goal is to highlight the need for strong safeguards to protect against these threats, which requires continuous research and development to improve the robustness of quantum cryptography algorithms. The experimental investigation includes analyzing crucial parameters, including quantum channel length, loss, QKD protocol, quantum bit error rate (QBER), signal-to-noise ratio (SNR), as well as attack parameters such as probability of photon number splitting (PNS), eavesdropper distance, and detection efficiency. The evaluation includes performance indicators such as secure key rate, quantum bit error rate (QBER) vs distance, vulnerability to photon number splitting (PNS) attacks, and the influence on the pace of key generation.
Quantum communication, leveraging the principles of quantum mechanics, offers unparalleled security and efficiency for data transmission. This study integrates quantum algorithms with photonic quantum key distribution (QKD) protocols, focusing on the Z-gate optical qubit algorithm and the SARG04 protocol. The Z-gate, a phase-flip operator, plays a pivotal role in maintaining coherence in photonic qubits, while the SARG04 protocol enhances security against photon-number-splitting (PNS) attacks. Simulations demonstrate that the Z-gate algorithm optimizes coherence times up to 0.995 ms, enabling longer quantum communication distances of approximately 150 km under ideal conditions. Concurrently, the SARG04 protocol generates secure keys of varying lengths (5 bits to 52 bits) depending on transmitted qubits and matching bases. By integrating these methodologies, this research aims to enhance the robustness and scalability of photonic QKD systems, bridging theoretical insights with practical implementations in quantum security.
Quantum Key Distribution (QKD) leverages quantum mechanical principles to establish information-theoretically secure cryptographic keys. The cornerstone BB84 protocol, however, suffers from key rate degradation due to the mandatory discarding of erroneous bits during post-processing. This paper presents an enhanced BB84 protocol incorporating a Tagging and Correction Method that systematically tracks, classifies, and corrects errors rather than discarding them. This approach maximizes the key material retained from the quantum transmission. The protocol integrates decoy state analysis for robust detection of photon-number-splitting (PNS) attacks and concludes with privacy amplification to ensure informationtheoretic security. Experimental validation using a high-fidelity Qiskit simulation with a realistic depolarizing channel model demonstrates a significant improvement in key rate efficiency. In a simulated environment with 15% eavesdropper intervention, our method achieved a 7.8% higher key rate than standard BB84, while successfully maintaining the Quantum Bit Error Rate (QBER) below the 11% security threshold. This work establishes a more robust and efficient framework for practical QKD implementations.
Abstract The BB84 quantum key distribution (QKD) protocol sets the foundation for achieving secure communication against quantum threats. Since its inception, significant advancements have aimed towards frugal experimental implementations with enhanced security. In this paper, we report a passive polarization encoded BB84 protocol. By passively and randomly encoding the polarization states, the setup avoids active modulation and simplifies design with security standards analogous to entanglement-based QKD. The heralding of a probabilistic single-photon source ensures an extremely low probability of multi-photon emissions evading photon number-splitting attacks. The quality of the single-photon source and thus, the QKD setup is certified by the second-order correlation function, g (2) (0) = 0.006 ± 0.0002. Our protocol provides an optimisation trade-off between the conventional BB84 and the BBM92 protocol. The advantage relies on using fewer detectors (compared to the BBM92 protocol) and no reliance on active quantum random number generators (compared to the standard BB84) to drive Alice’s encoding scheme. Our implementation achieves a quantum bit error rate of 7% and a secure key rate of 5 kbps.
Physical implementations of quantum key distribution (QKD) protocols, like the Bennett-Brassard (BB84), are forced to use attenuated coherent quantum states, because the sources of single photon states are not functional yet for QKD applications. However, when using attenuated coherent states, the relatively high rate of multi-photonic pulses introduces vulnerabilities that can be exploited by the photon number splitting (PNS) attack to brake the quantum key. Some QKD protocols have been developed to be resistant to the PNS attack, like the decoy method, but those define a single photonic gain in the quantum channel. To overcome this limitation, we have developed a new QKD protocol, called ack-QKD, which is resistant to the PNS attack. Even more, it uses attenuated quantum states, but defines two interleaved photonic quantum flows to detect the eavesdropper activity by means of the quantum photonic error gain (QPEG) or the quantum bit error rate (QBER). The physical implementation of the ack-QKD is similar to the well-known BB84 protocol.