Edinburgh Napier University

  The original consensus algorithm-Proof of Work (PoW) has been widely utilized in the blockchain systems and is been adopted by many cryptocurrencies, such as Bitcoin and Ethereum, among many others. Nevertheless, the concept has received criticisms over its high energy consumption. This is induced by the necessity for all nodes in the network to communicate synchronously for consensus over the ledger state to be reached. Additionally, the concept has also shown clear limitations regarding performance and throughput. In trying to rectify this issue, the paper proposes the introduction of a new hybrid consensus protocol known as the Proof of Notarized Work (PoNW). The PoNW concept reduces the number of nodes that need to achieve consensus, thereby reducing the overall energy consumption in the current PoW. In addition, we propose using a decentralized random beacon to select nodes to participate in the mining process randomly. Therefore, our algorithm promises to achieve higher scalability and consistency levels without conceding its decentralization. When this is paired with a Byzantine Fault Tolerance (PBFT) verification, the system gains the ability to replace the probabilistic finality in current PoW with absolute finality in a matter of seconds, solving the issue of scalability. Finally, the study will look into the proposed algorithm's security and provides threats model to insure an acceptable failure probability. Results from the security analysis have shown that our consensus algorithm ensures forks cannot occur, and it remains secure and consistent even amid numerous attacks.