Quantum B Granted European Patent for Quantum Conference Key Agreement Protocol

en.Wedoany.com Reported - The European Patent Office (EPO) has granted European Patent EP 4462727, application number EP23461579, to Quantum B, Inc. (formerly Quantum Blockchains), a quantum cryptography and security company. The patent centers on a Quantum Conference Key Agreement (QCKA) protocol, the core idea of which is to enable mutually independent network nodes to form distributed consensus with the help of multipartite quantum entanglement, thereby replacing classical consensus mechanisms such as proof of work and voting algorithms.

The central quantum server is the hub of this architecture. It emits time-bin encoded photons and converts these photons into multi-qubit Greenberger-Horne-Zeilinger (GHZ) states. Participating nodes in the network obtain qubit measurement results via quantum links and then coordinate through classical internet channels. Each node performs local measurements on the distributed GHZ states and derives correlated bit values accordingly; only when the locally computed values form a majority consensus across the entire network will the nodes verify and execute operations on the shared data block.

The patent document lists technical specifications across three aspects: system components, quantum hardware and state generation, and consensus and network protocols. Regarding the entanglement architecture, the quantum hardware and state generation section corresponds to time-bin encoded photon emission and multi-qubit time-bin GHZ states; the consensus and network protocols section corresponds to multi-node quantum state distribution and centralized/server-assisted scheduling. Regarding the verification model, the quantum hardware and state generation section includes local qubit measurement results and entanglement-derived correlations; the consensus and network protocols section includes classical channel bit exchange and quantum-correlated majority voting. Regarding target applications, the quantum hardware and state generation section points to multi-party data sharing platforms and low-trust distributed databases; the consensus and network protocols section points to enterprise blockchain networks and multi-organization consensus nodes.

Quantum B is headquartered in Łódź and Lublin. Protocol development is led by CEO Mirek Sopek and co-inventor Miriam Kosik, with the aim of reducing the communication overhead caused by classical multi-party synchronization. The patent serves as one of the supports for Quantum B's broader hardware and software portfolio, which includes an emulated Quantum Key Distribution (pQKD) hardware platform. At the same time, the company participates in the EU-funded POSEIDON project, which focuses on post-quantum digital identity protection.