Multimode Continuous-Variable Quantum Key Distribution with CMOS-Compatible Photonic-Electronic Integration

Multiplexing and photonic-electronic integration offer a route to scalable and high-throughput quantum key distribution QKD networks through parallel transmission and compact hardware suited to volume manufacturing. Realizing this route requires multichannel transmitters and receivers, and a...

From Link Availability to Deadline-Constrained Key Service: A Feasibility Framework for Mobile Free-Space Quantum Key Distribution

Mobile free-space quantum key distribution QKD links can provide secret bits intermittently, whereas applications may need cryptographic key material at specified times. Optical feasibility, positive finite-key output, and deadline-compliant key service are consequently different claims. This...

FVQKD: A Formal Verification of Quantum Key Distribution Security in Rocq

Quantum key distribution QKD, whose security is derived from quantum mechanics rather than computational assumptions, is moving into standardization and commercial deployment. Yet its security guarantees rest on technically delicate proofs checked by hand. Formal verification closes this gap,...

Observable-Level Framework for Finite-Key Security in Coherent-One-Way Quantum Key Distribution

Practical security analysis of Coherent-One-Way COW quantum key distribution requires optical-device modeling, finite experimental statistics, and security inference to be treated consistently without conflating assumptions. We present a modular observable-level simulation framework organized...

Orchestrating Key Scarcity: Global Capacity Allocation in Hybrid QKD-PQC Networks

This article presents a Distributed Key Management System DKMS that provisions quantum-safe symmetric encryption keys to applications across a network. To overcome the distance and rate limitations inherent to Quantum Key Distribution QKD, the architecture adopts a hybrid design: it utilizes...

Loss-Tolerant Measurement-Device-Independent QKD over Untrusted Repeaters Via High-Dimensional Time-Bin Multiplexing

We propose a loss-tolerant measurement-device-independent quantum key distribution MDI-QKD protocol using time-bin-multiplexed single photons entangled with local qubits stored in nitrogen-vacancy NV centers. In each round, Alice and Bob each send a single multiplexed photon to an untrusted...

Experimental Measurement-Device-Independent Quantum Key Distribution with Flawed State-Preparation over 300 Km

Quantum key distribution QKD promises theoretically secure communication. However, it encounters challenges in implementation security and performance due to inevitable device imperfections. Since the proposal of measurement-device-independent MDI QKD, the critical step toward practical security ...

Robust Quantum Key Distribution with Imperfections in State Preparation and Characterization

Quantum key distribution QKD offers an approach for secure communication over quantum channels, based on the principles of quantum mechanics. However, the inevitable imperfections in QKD systems can introduce critical vulnerabilities, posing significant challenges to the deployment of QKD in term...

CV-QKD with Noisy Coherent States and Realistic Displacement Receivers

Near-optimal binary coherent state discrimination can be achieved by performing a displacement operation followed by photon detection. This displacement serves as a control parameter that can be tuned to optimize a chosen figure of merit, which makes such receivers attractive beyond state...

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,...

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...

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...

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...