Key Reconciliation with RC-LDPC/Error Estimation for Satellite-Based FSO/QKD Systems

Satellite-based free-space optics FSO quantum key distribution QKD systems have recently attracted significant research interest due to their potential to enable globally secured applications. However, the inherent uncertainty of FSO channels, caused by weather conditions and satellite mobility,...

Security Framework for Practical Quantum Key Distribution with Imperfect Devices

Practical quantum key distribution QKD systems inevitably exhibit imperfections in both the source and detector. At the same time, the behavior of these imperfect devices is never exactly known due to characterization uncertainty, parameter fluctuations, and potential influence by an adversary. I...

Unconditional Security of Discrete-Modulated CV-QKD from Infinite-Dimensional MEAT

Discrete-Modulated DM Continuous-Variable CV Quantum Key Distribution QKD is an experimentally attractive approach to quantum cryptography, offering high key rates over metropolitan-scale distances while relying on state-of-the-art telecom infrastructure. However, a fundamental gap has remained...

Beyond the Quantum Promise: A Security Analysis of Classical Control in Quantum Key Distribution

Quantum Key Distribution QKD protocols provide information-theoretic security by using quantum mechanical principles. Yet QKD is fundamentally a hybrid protocol: its security depends on the correct integration of the quantum phase with classical post-processing. While ETSI and ITUT specifications...

The Finite Key Effect of Side-Channel-Secure Quantum Key Distribution beyond Post-Selection Technique

By applying the framework of entropic uncertainty relation EUR and the Quantum Leftover Hash Lemma QLHL, we introduce a security-proof method for variable-length side-channel-secure SCS quantum key distribution QKD against coherent attacks. This method reframes composable security as a statistica...

Practical Countermeasure against Attacks Exploiting Detection Efficiency Mismatch in Quantum Key Distribution

We demonstrate a practical countermeasure against a well-known class of attacks on quantum key distribution QKD systems that exploit detection efficiency mismatch, where the receiver's detectors do not exhibit identical responses to incoming photons across all degrees of freedom. This class of...

Twin-Field Quantum Key Distribution: Protocols, Security, and Open Problems

Twin-Field Quantum Key Distribution TF-QKD has emerged as a potential protocol for long distance secure communication, overcoming the rate-distance limitations of conventional quantum key distribution without requiring trusted repeaters. By having two parties transmit phase encoded weak coherent...