Abstract Since the 80 s when it was first proposed, Quantum Key Distribution (QKD) elicited great interest in the field of cryptography as a unique procedure for key generation that could in principle guarantee unconditionally secure communication “by the laws of Physics”. In the last fifteen years commercial solutions have started appearing on the market, showing that practical implementations of the protocol were not only possible but also competitive in terms of security and achievable secret-key rate. In this work we describe a simulation of the historical QKD protocol E91 on the IBM Quantum platform, making use of the qubit formalism to represent the quantum states received by two communicating nodes. Having implemented also the post-processing steps for the error correction and the privacy amplification, this model can represent a simple stand-alone tool to study the performance not only of one-to-one communication but of more complex systems that rely on QKD for security, one above all QKD networks.
Abstract Since the 80 s when it was first proposed, Quantum Key Distribution (QKD) elicited great interest in the field of cryptography as a unique procedure for key generation that could in principle guarantee unconditionally secure communication “by the laws of Physics”. In the last fifteen years commercial solutions have started appearing on the market, showing that practical implementations of the protocol were not only possible but also competitive in terms of security and achievable secret-key rate. In this work we describe a simulation of the historical QKD protocol E91 on the IBM Quantum platform, making use of the qubit formalism to represent the quantum states received by two communicating nodes. Having implemented also the post-processing steps for the error correction and the privacy amplification, this model can represent a simple stand-alone tool to study the performance not only of one-to-one communication but of more complex systems that rely on QKD for security, one above all QKD networks.
Quantum computing poses significant threats to conventional cryptographic techniques such as RSA and AES, motivating the need for quantum secure communication methods. Quantum Key Distribution (QKD) offers information theoretic security based on fundamental quantum principles. This paper presents a simulation-based analysis of well-known QKD protocols, namely BB84, B92, and E91, using the IBM Qiskit framework. Realistic quantum channel effects, including noise, decoherence, and eavesdropping, are modeled to evaluate protocol performance. Key metrics such as error rate, secret key generation, and security characteristics are analyzed and compared. The study highlights practical challenges in QKD implementation, including hardware limitations and channel losses, and discusses insights toward scalable and robust quantum communication systems. The results support the feasibility of QKD as a promising solution for secure communication in the quantum era.
In recent years, quantum computing technologies have steadily matured and have begun to find practical applications across various domains. One important area is network communication security, where Quantum Key Distribution (QKD) enables communicating parties to establish a shared secret that can then be used to generate symmetric keys for subsequent encryption and decryption. This study focuses on implementing and comparing two well-known QKD protocols, namely BB84 and E91, within an actual quantum computing environment. It also proposes the use of SX gate operations to generate uniform quantum superposition states. By leveraging the properties of quantum superposition and quantum entanglement, the study illustrates how communicating parties can securely obtain a shared secret while preventing adversaries from intercepting it. The experiments are conducted using the IBM Quantum Platform to demonstrate the feasibility of the BB84 and E91 protocols on actual quantum hardware. The evaluation considers several metrics, including entropy, Independent and Identically Distributed (IID), and error-rate verifications.
The promise of unconditional security in the Quantum Key Distribution (QKD) depends on the availability of an authenticated classical channel. However, practical implementations often overlook this requirement or rely on computational assumptions that compromise long-term security. To overcome these challenges, this paper presents Entanglement-Based Authenticated Quantum Key Distribution (EAQKD), a novel protocol that addresses critical security and practical limitations in quantum cryptographic key exchange. Our approach integrates quantum entanglement distribution with information-theoretic authentication. We evaluate EAQKD's performance through a comprehensive discrete-event simulation framework modeled on realistic channel characteristics and experimental device parameters. Our modeling incorporates parameters from practical quantum optics setups, including SPDC entanglement sources, superconducting nanowire detectors, and fiber channel imperfections. Our results show quantum bit error rates consistently below the 11% security threshold (ranging from 1.86% at 10 km to 9.27% at 200 km), with secure key rates achieving 1.12×105 bits/s at short distances and maintaining practical rates of 9.8 bits/s at 200 km. When integrated with quantum repeater architectures, our analysis projects that EAQKD can extend secure communication beyond 500 km while providing information-theoretic security guarantees. Comparative analysis against the BB84, E91, and Twin-Field QKD protocols demonstrates EAQKD's superior balance of security, practical performance, and implementation robustness. This work advances quantum cryptography by providing a rigorously analyzed engineering reference for secure key distribution in future quantum communication networks.
By utilizing concepts from quantum physics like entanglement and superposition, quantum cryptography is revolutionizing data security. This study focuses on the application of classical computational models for simulation-based analysis of Quantum Key Distribution (QKD) protocols, namely BB84 and E91. By taking use of quantum features, QKD makes secure key exchange possible and guarantees that any effort at eavesdropping may be identified because of the disruption of quantum states. In order to assess how quantum communication channels behave under different noise and attack scenarios, the study models and simulates these channels. The study evaluates the efficacy and robustness of BB84 and E91 protocols in practical network settings by contrasting their performance and error tolerance. In order to determine if integrating quantum-secured systems with current classical infrastructures is feasible, scalability issues are also investigated. These simulations’ outcomes shed light on feasible security levels, resource needs, and workable deployment tactics. In the end, this research highlights how quantum cryptography may advance the basis for next-generation secure information networks by bridging the gap between theoretical quantum security models and real-world communication systems with the use of strong simulation frameworks.
Abstract Quantum key distribution (QKD) enables information-theoretically secure communication based on the laws of quantum physics. Although QKD remains an active area of research, ongoing commercialization efforts underscore its growing significance in modern physics and communication. This mini-review provides a brief overview of existing multi-user QKD networks and ongoing developments, with an emphasis on field tests. We examine different network architectures. In addition, we explore the prospect of photonic integrated circuits (PICs) and their current capabilities in QKD implementations. We also present various post-processing algorithms focusing on error correction (EC) and privacy amplification (PA), as well as implementations of these protocols in different experiments. Finally, we conclude by providing an overview of our quantum network and discussing setup choices from our recent field tests.
The paper addresses the development of quantum networks (QNs) with entanglementbased Quantum Key Distribution (QKD) protocols.The entanglement (the correlation among the quantum states of several particles) is an essential principle of quantum mechanics.This property has a major impact on the fields of application of QKD systems, the secured cryptographic key exchange and passive attack detection, while it can also be applied in quantum teleportation.Starting from the existing achievements in Europe (a QN for connecting several cities in Randstad, one of the main metropolitan regions in the Netherlands), a case study for a simulated entanglement-based QN is presented, including an ideal scenario (with noiseless QKD) and a nonideal one (with noisy QKD).The experimental settings are differentiated through the link and node fidelity.The simulation process produces general statistics, sender statistics, receiver statistics, the QBER (Quantum Bit Error Rate) and also the raw keys as generated by the entanglement-based protocol.No post-processing (non-quantic) phase is considered for the analyzed setting.Such simulations are useful for properly adjusting the design of a QN while taking into account its expected performance with respect to the non-ideal use-cases with errors that could be caused by an imperfect hardware or by potential eavesdropping actions.