Abstract this paper proposes an optimized Quantum Key Distribution (QKD) protocol using entanglement swapping techniques to extend transmission range and improve error correction. Additionally, integrates an advanced error correction technique which is Low Density Parity Check (LDPC) and multi-hop quantum repeaters for more enhancement of the protocol performance. Hybrid Quantum Classical Error Correction Methods is applied ensuring compatibility and optimal performance and to manage the increased complexity. Simulations prove that 25% improvement in transmission distance with entanglement swapping. 50% improvement with advanced error correction and a 100% improvement with multi-hop quantum repeaters compared to existing protocols. These discoveries are supported by both theoretical analysis and simulation results, indicating significant decreases in error rates and extensions in maximum transmission distances. Comparative analysis made with existing protocols and that demonstrated the superiority of proposed approach in terms of extended secure communication distance, higher key generation rate and improved resilience to attacks.
Abstract this paper proposes an optimized Quantum Key Distribution (QKD) protocol using entanglement swapping techniques to extend transmission range and improve error correction. Additionally, integrates an advanced error correction technique which is Low Density Parity Check (LDPC) and multi-hop quantum repeaters for more enhancement of the protocol performance. Hybrid Quantum Classical Error Correction Methods is applied ensuring compatibility and optimal performance and to manage the increased complexity. Simulations prove that 25% improvement in transmission distance with entanglement swapping. 50% improvement with advanced error correction and a 100% improvement with multi-hop quantum repeaters compared to existing protocols. These discoveries are supported by both theoretical analysis and simulation results, indicating significant decreases in error rates and extensions in maximum transmission distances. Comparative analysis made with existing protocols and that demonstrated the superiority of proposed approach in terms of extended secure communication distance, higher key generation rate and improved resilience to attacks.
With the increasing complexity of cyber threats and the emergence of quantum computing, enhancing secure communication is essential. This study explores an effective hybrid quantum key distribution (QKD) protocol that integrates photonic and atomic systems to leverage their respective strengths. The concept of symmetry plays a crucial role in this context, as it underpins the principles of entanglement and the balance between key generation and error correction. The photonic system is used for the initial key generation, while the atomic system facilitates entanglement swapping, error correction, and privacy amplification. The comprehensive theoretical framework encompasses key components, detailed security proofs, performance metrics, and an analysis of system vulnerabilities, illustrating the resilience of the hybrid protocol against potential threats. Extensive experimental studies demonstrate that the hybrid QKD protocol seamlessly integrates photonic and atomic systems, enabling secure key distribution with minimal errors and loss rates over long distances. This combination of the two systems reveals exceptional resilience against eavesdropping, significantly improving both security and robustness compared with traditional QKD protocols. Consequently, this makes it a compelling solution for secure communication in the increasingly digital world.
This paper investigates a novel approach to enhancing cryptographic key distribution using entanglement swapping. Current quantum key distribution (QKD) protocols are often limited by distance due to signal loss and decoherence during the direct transmission of entangled photons. This research proposes a protocol that overcomes these limitations by employing entanglement swapping, effectively extending the range of secure key exchange. The core of the method involves strategically swapping entangled pairs to create correlated states between distant parties, circumventing the need for direct transmission over long distances. Mathematical formulations detailing the protocol's key steps, including the quantum operations and measurement outcomes, are presented. The analysis demonstrates a pathway towards significantly increasing the practical range of QKD systems, offering a potential solution for secure communication over greater distances. The theoretical framework presented here lays the groundwork for future experimental implementations and further optimization of entanglement swapping protocols for enhanced QKD performance.
This paper proposes a novel quantum key distribution (QKD) protocol leveraging quantum entanglement for enhanced security and reduced key exchange latency. The protocol utilizes entangled photon pairs to generate a shared key, combined with quantum error correction codes for reliable key recovery. The core innovation lies in the efficient use of entanglement for key generation and transmission, offering a significant improvement over classical key exchange methods. The protocol's performance is analyzed, demonstrating its potential to bolster security against eavesdropping attacks and minimize the time required to establish a secure key. The design addresses key limitations of existing QKD protocols, particularly those related to distance and efficiency. Furthermore, the integration of quantum error correction directly contributes to a more robust and practical system. This research contributes to the ongoing advancements in quantum cryptography and represents a critical step towards secure quantum communication networks.
Quantum Key Distribution protocols have been essential for the purpose of creating secure channels for long-distance transmission of quantum information. On the basis of ideas of quantum teleportation, this paper presents a novel quantum communication protocol utilizing the quantum entanglement and classical communication channels. Also, this paper aims to increase key generation rate and distance, achieve longer communication distances and higher key production compared to traditional QKD methods, improve resilience against eavesdropping and optimize system performance. Quantum teleportation ensures the secure transfer of quantum states without exposing them to potential eavesdropping or interception, offering a higher level of security compared to traditional qubit-based protocols. This involves a thorough investigation of the Qiskit circuit implementations, operational procedures, and mathematical underpinnings of the protocol. Also, a thorough study of the protocol’s performance with respected to some of the existing protocols like BB84, E91 and others using various metrics like QBER, key generation rate, adversarial resilience and. This project advances Quantum Key Distribution systems and established the foundation for secure quantum communication networks.
Abstract: This chapter explores the engineering of quantum repeaters, a critical technology for enabling secure and scalable long-distance quantum communication. Quantum repeaters extend the range of quantum communication networks by preserving entanglement and mitigating signal loss over large distances. The chapter covers the key principles of entanglement swapping, quantum memory, and quantum error correction, which are essential for maintaining the integrity of quantum states. It also examines advanced repeater architectures, including multi-mode repeaters and entanglement purification techniques, to improve scalability and robustness. Case studies highlight real-world implementations of quantum repeaters in quantum key distribution (QKD) networks, demonstrating their role in achieving secure global communication. Keywords: quantum repeaters, long-distance quantum communication, entanglement swapping, quantum memory, quantum error correction, entanglement purification, multi-mode repeaters, quantum key distribution, QKD, scalable quantum networks, secure communication.
Quantum communications enable secure key transmission and entanglement distribution, but their rates and maximum transmission distances are limited due to the losses and noise introduced by quantum channels. Various techniques have been developed to address these limitations, tailored to the platform and the nature of the decoherence. In this thesis, we explore ways to enhance the performance of quantum communications, with a particular focus on increasing the key rates and transmission distances in quantum key distribution (QKD), a method that leverages quantum mechanics to securely share keys between trusted parties. Additionally, we aim to improve the purity of entangled states shared between two parties, contributing to broader advancements in quantum communications. We begin by introducing a software-enhanced continuous-variable QKD (CV-QKD) protocol, where keys are encoded onto the phase and amplitude degrees of the optical field. This protocol enhances both transmission distance and key rates through a post-selection method employing arbitrary filters, experimentally demonstrated on two different platforms. Its adaptability makes it highly promising, as it can be implemented on existing CV-QKD platforms and dynamically optimises key rates for rapidly changing channels. We then present a protocol for the pure-loss channel leveraging quantum repeaters to mitigate the channel losses by segmenting the total communication distance into smaller, more manageable intervals. This repeater-like protocol introduces a more efficient entanglement-swapping measurement at the repeater station than the state-of-the-art twin-field protocols. Instead of polarisation encoding, our protocol relies on encoding keys in the photon-number basis, optimising the states to achieve the highest key rates for each distance. Notably, this protocol shows strong potential for improving long-distance quantum communication by surpassing the capacity of the direct communication channel at a shorter distance than the existing repeater protocols such as twin-field QKD while achieving an overall higher transmission distance. Finally, in this thesis, we demonstrate that for the Pauli-dephasing channel, placing a node in the middle of the quantum channel to perform a Bell-state measurement as an entanglement-swapping operation does not result in improved key rates, even with reduced decoherence. As a result, we propose an entanglement purification protocol that refines a larger set of noisy entangled states into a smaller set of high-fidelity ones using local operations and classical communication. This purification protocol builds upon earlier purification methods, extending their application from two Bell pairs to any number of Bell pairs and thereby achieving the capacity of the dephasing channel. Through numerous recursive iterations, it produces near-perfect Bell pairs, making it well-suited for quantum repeaters and correcting dephasing errors in quantum computers.