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Journal of Physics Conference Series

Development of Quantum Key Distribution (QKD) with E91 Protocol for Future Secure Quantum Networks

Muhammad Fajri Zulfa, Khoirul Anwar

Published Apr 1, 2025• 14 citations
Publisher

Abstract

Abstract This paper investigates practical performances of the Ekert 91 protocol (E91) for future secure quantum networks. To seek future possible improvement, we investigate the important different principles of E91 and Bennet-Brasard (BB84) protocols. We perform a series of computer simulations to evaluate the performances of them and investigate the practical parameters. Furthermore, we simulate the E91 protocol using real-world practical scenarios involving eavesdropping and quantum channel errors. We present two scenarios: (1) the performance with eavesdropper interception under a perfect channel and (2) the performances with eavesdropper interception combined with channel errors. We found that: (i) the E91 protocol produces fewer keys compared to the BB84 protocol but does not require verification between two parties, (ii) the E91 protocol enhances security due to the utilization of Clauser, Horne, Shimony, and Holt (CHSH) inequality, and (iii) both eavesdropper and channel errors can impact the less production of keys obtained during the keys production.

DOI
10.1088/1742-6596/2980/1/012038

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Abstract This paper investigates practical performances of the Ekert 91 protocol (E91) for future secure quantum networks. To seek future possible improvement, we investigate the important different principles of E91 and Bennet-Brasard (BB84) protocols. We perform a series of computer simulations to evaluate the performances of them and investigate the practical parameters. Furthermore, we simulate the E91 protocol using real-world practical scenarios involving eavesdropping and quantum channel errors. We present two scenarios: (1) the performance with eavesdropper interception under a perfect channel and (2) the performances with eavesdropper interception combined with channel errors. We found that: (i) the E91 protocol produces fewer keys compared to the BB84 protocol but does not require verification between two parties, (ii) the E91 protocol enhances security due to the utilization of Clauser, Horne, Shimony, and Holt (CHSH) inequality, and (iii) both eavesdropper and channel errors can impact the less production of keys obtained during the keys production.
Quantum cryptography is anticipated to drive substantial advancements in cybersecurity. The impending arrival of quantum cryptography compromises current encryption methods, possibly compromising the effectiveness of traditional key management-based security protocols. One fundamental Quantum Key Distribution (QKD) protocol, BB84, encounters challenges when operating with fewer Quantum bits (Qubits) and bases that only support up to 8 Qubits. This limitation weakens the system’s security, making brute force, intercept, and resend attacks less challenging. Consequently, this study proposes a method to enhance the security of the BB84 protocol, to reduce susceptibility to attacks and eavesdropping. The improved BB84 protocol utilizes 9, 12, and 16 quantum bits along with two, and three bases to significantly bolster security. This allows authorized parties to eliminate the use of compromised keys. Additionally, the study implements the E91 QKD protocol utilizing the Entanglement Pair Generation (EPR) method to produce secure keys. While the existing E91 protocol ensures security through Bell’s theorem and Bell’s inequality, it overlooks the impact of noise, leading to inaccuracies in eavesdropper detection. To address this, the study introduces an additional security measure. Whenever an eavesdropper attempts to measure the quantum state, the proposed E91 protocol collapses its state from$\vert 10\rangle tototo\vert 11\rangle ,settingthefirstQubitto, setting the first Qubit to,settingthefirstQubitto\vert 1\rangle andtheotherQubittoand the other Qubit toandtheotherQubitto\vert 0\rangle $, thus providing the eavesdropper with incorrect information, accompanied by a phase angle of$15\pi $/8. This leads to a misconception, preventing eavesdroppers from obtaining useful details about transferred quantum states. Additionally, considering that the proposed E91 protocol relies on entangled particles and utilizes double Qubit gates, which are inherently noisier than single Qubit gates and more susceptible to quantum decoherence, this study employs error mitigation techniques during the final measurement to predict outcomes more efficiently.
Quantum Key Distribution (QKD) is a ground-breaking solution to secure communication that uses fundamental quantum mechanics principles to allow for the exchange of cryptographic keys with provable security. BB84 and E91, two of the first and most significant QKD systems, presented two different approaches to using quantum characteristics to prevent eavesdropping and maintain confidentiality. A brief literature review of these two fundamental protocols is presented in this paper. Bennett and Brassard created the BB84 protocol in 1984. It uses polarized photons and detects interception using the uncertainty principle. On the other hand, Bell's theorem and entangled photon pairs are used in the E91 protocol, which was first presented by Ekert in 1991, to guarantee the integrity of the shared key. Each protocol's theoretical foundations, methods of implementation, and relative benefits has been explored in addition to how they have influenced contemporary quantum cryptography systems. This paper attempts to give a basic understanding of QKD and its early advancements by examining the similarities and differences between BB84 and E91.
Quantum Key Distribution (QKD) brings a revolutionary approach to secure communication by using the principles of quantum mechanics to safeguard the transfer of cryptographic keys.This project explores the practical deployment of two foundational QKD protocols: BB84 and E91.The BB84 protocol secures key distribution through photon polarization, while the E91 protocol uses the unique properties of quantum entanglement to enhance resistance to eavesdropping.By contrasting these quantum methods with classical cryptographic techniques, the study provides a comprehensive look at their relative strengths and limitations.Practical implementation and thorough analysis demonstrate that QKD protocols offer significant advantages in preventing interception, shedding light on their potential role in advancing cryptographic security in the era of quantum technology.This research not only assesses the practical challenges of implementing QKD but also considers future advancements that could broaden its real-world applications.
The secure transfer of keys between two parties, is one of the primary problems in cryptography. The possibility that the key can be manipulated or intercepted by way of an eavesdropper is the cause for the concern. A promising way to this problem is Quantum Key Distribution (QKD). The secure distribution of keys that may be used to encrypt and decrypt messages is made feasible by this approach, which makes use of the idea of quantum mechanics. QKD offers a degree of protection that can not be done by means of classical cryptography techniques, and has remarkable capability for application in a scope of fields in which secure correspondence is crucial. QKD is a field of study that has brought various conventions pointed toward empowering the safe alternate of cryptographic keys between two parties, Alice and Bob. Two key protocols within this field are the BB84 which was designed by Bennett and Brassard and E91 which was proposed by Ekert. While other protocols have been developed, many draw inspiration from these two foundational approaches. We focused specifically on the E91 protocol and explored its potential for the safe transfer of entangled pairs within computer networks. This protocol utilizes entanglement between particles as a means of verifying the security of the key exchange. Our investigation centered around testing the entanglement swapping for two particles using the E91 protocol, with the aim of developing a novel method for the secure transmission of entangled pairs via computer networks. Our findings suggest promising avenues for future work in implementing secure entanglement swapping in practical applications.
This paper focuses on the implementation and comparative analysis of two widely studied QKD protocols. The BB84 and E91 protocols are security measures that were devised back in the 1980s and 90s by experts like Charles Bennett and Ekaterina S. Ekert. This paper demonstrates with Qiskit protocol implementation documentation and simulation results together with extensive security analysis how BB84 and E91 protocols can be utilized through an open-source quantum computing framework developed by IBM. This paper aims to examine the BB84 and E91 protocol resistance to eavesdropping invasions while testing their performance across different communication ranges. We utilize quantum superposition to encode information into qubits during BB84 protocol implementation which allows us to simulate an intercept-resend attack to determine its vulnerability. Research shows that BB84 provides simpler execution yet suffers from more eavesdropping attacks especially at extended distances through increased error rates from interception methods. E91 protocol achieves detection of eavesdropping by distributing entangled qubits between two parties so measurements of those qubits reveal tampering through their outcome correlations. Our experimental findings confirm that E91 delivers enhanced security capabilities through its ability to keep errors minimal across longer distances thus demonstrating resistance against distance-related threats. The comparative analysis underscores the strengths and limitations of each protocol. BB84, despite its simplicity and ease of implementation, shows diminished security over longer distances. E91, which uses the non-local properties of entangled qubits, offers enhanced protection for long-distance communication, making it a more practical choice for robust QKD systems.
Quantum Key Distribution (QKD) is a ground-breaking solution to secure communication that uses fundamental quantum mechanics principles to allow for the exchange of cryptographic keys with provable security. BB84 and E91, two of the first and most significant QKD systems, presented two different approaches to using quantum characteristics to prevent eavesdropping and maintain confidentiality. A brief literature review of these two fundamental protocols is presented in this paper. Bennett and Brassard created the BB84 protocol in 1984. It uses polarized photons and detects interception using the uncertainty principle. On the other hand, Bell's theorem and entangled photon pairs are used in the E91 protocol, which was first presented by Ekert in 1991, to guarantee the integrity of the shared key. Each protocol's theoretical foundations, methods of implementation, and relative benefits has been explored in addition to how they have influenced contemporary quantum cryptography systems. This paper attempts to give a basic understanding of QKD and its early advancements by examining the similarities and differences between BB84 and E91.