Quantum Blockchain Consensus

We propose a novel consensus mechanism utilizing the quantum properties of qubits. This move from classical computing to quantum computing is shown to theoretically enhance the scalability and speed of distributed consensus as well as improve security and be a potential solution for the problem of blockchain interoperability. Using this method may circumvent the common problem known as the Blockchain Trilemma, enhancing scalability and speed without sacrificing de-centralization or byzantine fault tolerance. Consensus speed and scalability is shown by removing the need for multicast responses and exploiting quantum properties to ensure that only a single multicast is required. We also leverage work done on the E91 quantum key distribution protocol to securely transmit values and prevent a man-in-the-middle attack or system disturbance, enhancing confidentiality and integrity of transmitted information. Distributed ledger interoperability is explored by proposing a system to achieve a verifiable bridge for private transactions between a small private network and its corresponding consortium network. A proof-of-concept using IBM’s Qskit is shown from which initial results appear to show a strong sensitivity to non-consensus which could be useful in many applications. The present practical feasibility of the above is shown and future work is explored. The work was in collaboration with OneConnect Financial Technology Co. Ltd.