Entanglement Verification in QKD

Marius Nagy, Selim G. Akl

Hauke Häseler, Tobias Moroder, Johannes Rigas +2 more

Ming‐Xing Luo

Yanbao Zhang, Norbert Lütkenhaus

The security analysis of quantum key distribution is difficult to perform when there is efficiency mismatch between various threshold detectors involved in an experimental setup. Even the verification that the device actually performs in the quantum domain, referred to as the task of entanglement verification, is hard to perform. In this article we provide such an entanglement-verification method for characterized detection-efficiency mismatch. Our method does not rely on a cutoff of photon numbers in the optical signal. It can be applied independently of the degrees of freedom involved, thus covering, for example, efficiency mismatch in polarization and time-bin modes, but also in spatial modes. The evaluation of typical experimental scenarios suggests that an increase of detection-efficiency mismatch will drive the performance of a given setup out of the quantum domain.

Jincheng Zhang

This paper proposes a novel approach to distributed data verification leveraging the unique properties of quantum entanglement. The core claim is that a highly secure distributed data verification system can be achieved without the need for shared keys, even when individual nodes are compromised. The proposed mechanism involves constructing a network of multiple quantum processors, each storing a portion of the data. Utilizing entangled states, real-time verification of relationships between data blocks is performed, and any detected alteration is immediately flagged. Quantum Key Distribution (QKD) protocols based on entangled states serve as the underlying communication foundation. This approach fundamentally differs from existing distributed data verification methods, which rely on key exchange and are therefore vulnerable to key compromise. The inherent principles of quantum mechanics provide a stronger security guarantee, theoretically offering superior resistance to attacks. This system aims to establish a robust and secure data integrity framework in scenarios demanding high levels of trust and protection against malicious manipulation.