Long-range quantum key exchange with an untrusted satellite.

Long-range QKD without trusted nodes is not possible with current technology

The ARQ19 patent’s claim of achieving long-range quantum key distribution without trusted nodes is unfounded because it relies on an unexplained confidential classical channel between end users that cannot be quantum-based due to distance limitations, making the system’s security ultimately dependent on this non-quantum channel rather than achieving true quantum security.

Quantum communication chain within a network.

Composable Security Analysis of Gaussian Quantum Networks

A theoretical study advancing the composable security analysis of Gaussian quantum networks in finite-size regimes, introducing a novel parameter estimation methodology based on end-user data sharing, while demonstrating potential breakthroughs in surpassing the PLOB bound through quantum amplifier-assisted chains, though practical implementation remains challenging.

Source comparison for three main QKD schemes.

Enhancing quantum cryptography with quantum dot single-photon sources

Quantum dot-based single-photon sources offer superior security for quantum cryptography through their unique combination of on-demand emission, high brightness, low multiphoton contribution, and tunable coherence in photon-number states, outperforming traditional Poisson-distributed sources across multiple cryptographic primitives.