Quantum communication uses photons to transmit quantum bits (qubits) over long distances. By using this quantum technology, quantum key distribution (QKD), a secure communication protocol, ensures the security of encryption key exchange. Due to noise and eavesdropping in the quantum channel, errors can occur in the shared qubits after QKD key agreement phase. Therefore, we need a key verification phase to deal with inconsistent qubits (i.e. the wrong qubits at the receiving end). This key verification is also called information reconciliation. Recently, some reconciliation algorithms in QKD (RQKD) using polynomial consistency have been proposed. These RQKDs use the consistency property to find the correct polynomial (converted from the qubits) and then check the correctness of other qubits based on this polynomial to achieve reconciliation. All previous consistency-based RQKDs required such an extra step to check the correctness of other qubits after finding the correct polynomial. In this paper, we propose Enhanced RQKD (ERQKD), which uses consistency in a new way to improve key verification efficiency without requiring additional checking steps. Theoretical analysis and experiments indeed show that our ERQKD outperforms the two previous RQKDs.
Quantum communication uses photons to transmit quantum bits (qubits) over long distances. By using this quantum technology, quantum key distribution (QKD), a secure communication protocol, ensures the security of encryption key exchange. Due to noise and eavesdropping in the quantum channel, errors can occur in the shared qubits after QKD key agreement phase. Therefore, we need a key verification phase to deal with inconsistent qubits (i.e. the wrong qubits at the receiving end). This key verification is also called information reconciliation. Recently, some reconciliation algorithms in QKD (RQKD) using polynomial consistency have been proposed. These RQKDs use the consistency property to find the correct polynomial (converted from the qubits) and then check the correctness of other qubits based on this polynomial to achieve reconciliation. All previous consistency-based RQKDs required such an extra step to check the correctness of other qubits after finding the correct polynomial. In this paper, we propose Enhanced RQKD (ERQKD), which uses consistency in a new way to improve key verification efficiency without requiring additional checking steps. Theoretical analysis and experiments indeed show that our ERQKD outperforms the two previous RQKDs.
Quantum key distribution (QKD) is a secure communication protocol that uses quantum bits (qubits) to ensure the security of key exchange between two entities (Alice and Bob). Their shared qubits may suffer from errors due to noise and eavesdropping in the quantum channels. After the QKD key agreement phase, Alice's key may not be different from Bob's key. Therefore, we need key verification to deal with the inconsistent qubits (i.e. the wrong qubits at receiver end). This key verification process is also known as information reconciliation. Recently, Kurt et al. proposed a reconciliation in QKD (RQKD) by using the polynomial consistency property. In this paper, we propose an enhanced RQKD (ERQKD) to improve key verification. Our method is still based on polynomial consistency, but uses the properties of consistency in a different way to obtain better key verification efficiency.
Quantum Key Distribution (QKD) could share a secret key between two distant nodes Alice and Bob. In the presence of an eavesdropper and noisy channel, Alice’s key may not be the same as Bob’s key. Thus, QKD protocol has to provide not only the distribution in key agreement phase but also the integrity in key verification phase. Error reconciliation is often used in QKD to share identical keys between Alice and Bob in key verification phase. Recently, Kurt et al. introduce a reconciliation algorithm for QKD (RQKD) to prevent error propagation in some previous reconciliation algorithms. Kurt et al.’s RQKD is a block-wise operation, and uses polynomial interpolation for reconciliation. However, if the x-axis values of polynomials are the same the blocks are removed. In this paper, we propose an enhanced RQKD (ERQKD) to deal with this weakness. When using polynomial-interpolation approach for reconciliation, our ERQKD without deleting block improves the efficiency of sharing qubits.
Abstract In quantum cryptography, secret communications are delivered through a quantum channel. One of the most important breakthroughs in quantum cryptography has been the quantum key distribution (QKD). This process enables two distant parties to share secure communications based on physical laws. However, eavesdroppers can still interrupt the communication. To overcome this, we propose a different way to detect the presence of Eve through the polynomial interpolation technique. This technique also allows us for key verification. This approach prevents the receiver as well as the intruder from discovering the sender’s fundamental basis. To fully utilize IBM quantum computers’ quantum computing capabilities, this paper attempts to show % error against alpha (strength of eavesdropping) and the impact of noise on the success probability of the desired key bits. Furthermore, the success probability under depolarizing noise is explained for different qubit counts. In the enhanced QKD protocol, using polynomial interpolation for reconciliation shows a 50% probability of successful key generation. This is even when the noise is increased to the maximum capacity.
Quantum key distribution (QKD) enables unconditional secure communication by exploiting the principles of quantum mechanics. However, existing reconciliation protocols face a trade-off between error correction efficiency and information leakage. To address this challenge, we propose an enhanced QKD reconciliation scheme based on polynomial interpolation. The protocol introduces a block-wise algebraic structure to unify error detection and correction, significantly reducing interactive rounds while maintaining high efficiency. A comprehensive information-theoretic leakage model is established, covering polynomial interpolation, verification, and iterative error localization. To further ensure unconditional security, a cascaded privacy amplification mechanism is integrated, combining two compression stages tailored to reconciliation leakage and quantum channel leakage, respectively. Moreover, an adaptive parameter optimization strategy dynamically adjusts block size and polynomial order according to the quantum bit error rate (QBER), achieving robustness under diverse channel conditions. Theoretical analysis and simulations demonstrate that the proposed scheme achieves a secure key rate of 65–72% at QBER < 3%, outperforming the classical CASCADE protocol by 8–12%, and maintains 30–50% efficiency under moderate error rates. Computational complexity analysis shows performance comparable to LDPC-based approaches while offering superior leakage control. These results confirm that the proposed protocol provides a balanced trade-off among efficiency, security, and implementation complexity, making it suitable for deployment in practical QKD systems.
In this work, we propose a novel key reconciliation protocol for the quantum key distribution (QKD). Based on Newton's polynomial interpolation, the proposed protocol aims to correct all erroneous bits at the receiver without revealing information to the eavesdropper. We provide the exact frame error rate (FER) expression of the proposed protocol. The inherent nature of the proposed algorithm ensures correcting all erroneous bits if the algorithm succeeds. We present an information-theoretical proof that the revealed information during the key reconciliation process is equal to zero. We also provide a numerical comparison of our algorithm with the asymptotic performance of the error-correcting codes and two exemplary low-density-parity-check (LDPC) codes. The results highlight that our algorithm provides superior performance when compared to the LDPC codes, regardless of the distance between Alice and Bob. Furthermore, the proposed key reconciliation protocol is usable for the longer quantum link distances than the state-of-the-art protocols.
Quantum cryptography is the study of delivering secret communications across a quantum channel. Recently, Quantum Key Distribution (QKD) has been recognized as the most important breakthrough in quantum cryptography. This process facilitates two distant parties to share secure communications based on physical laws. The BB84 protocol was developed in 1984 and remains the most widely used among BB92, Ekert91, COW, and SARG04 protocols. However the practical security of QKD with imperfect devices have been widely discussed, and there are many ways to guarantee that generated key by QKD still provides unconditional security. This paper proposed a novel method that allows users to communicate while generating the secure keys as well as securing the transmission without any leakage of the data. In this approach sender will never reveal her basis, hence neither the receiver nor the intruder will get knowledge of the fundamental basis.Further to detect Eve, polynomial interpolation is also used as a key verification technique. In order to fully utilize the quantum computing capabilities provided by IBM quantum computers, the protocol is executed using the Qiskit backend for 45 qubits. This article discusses a plot of % error against alpha (strength of eavesdropping). As a result, different types of noise have been included, and the success probability of the desired key bits has been determined. Furthermore, the success probability under depolarizing noise is explained for different qubit counts.Last but not least, even when the applied noise is increased to maximum capacity, a 50% probability of successful key generation is still observed in an experiment.