An important consideration that is missing in section 7 A Blockchain Scheme is that the PoW must also be tied to the miner's receive address otherwise anyone could claim the reward as soon as the PoW was broadcast onto the network. A simple solution is to also hash the miner's receive address along with the previous block and transaction hash. This seems like a pretty major omission on the part of the authors and cast some doubt on the rest of the paper.