Enhancing Quantum Key Distribution Performance in the Presence of Noise

Quantum key distribution, which is based on the laws of physics, has revolutionized the protection of communication information. However, before QKD can be extensively utilized, a number of critical challenges must be overcome, namely, the noise of channels. Key qubits are distorted by passing through noisy channels, which leads to errors and significantly impact the security, which is the most crucial aspect of QKD. In this paper, we utilize quantum gates and environment-assisted measurement to enhance the performance of QKD in the presence of noise. We present the details of our methods for both prepare-and-measure (BB84) and entanglement-based (BBM92) QKD protocols to demonstrate how they can be combined with various types of common QKD protocols. We have considered applying quantum gates after the noisy channel to recover the damped key qubits and both before and after the noisy channel to prepare and recover the key qubits. We demonstrate the significant reduction in the error rate of the proposed schemes compared to QKD protocols with no protection. Furthermore, to achieve a protection scheme that is independent of the intensity of the noisy channel, we consider applying environment-assisted measurement to the noisy channel, followed by a recovery process via quantum gates, where explicit formula of the protection variable to achieve an error rate of zero is calculated and the corresponding success probability is analyzed. To assess our proposed schemes for BB84 and BBM92 protocols, we analyze three key performance indicators: error rate, QKD success probability, and eavesdropper’s success probability. These metrics provide insights into the effectiveness, correctness, and security of our methods, ensuring reliable and secure quantum communication.