Secure High-Rate Transaction Processing in Bitcoin

This paper addresses Bitcoin's inherent scalability limitations, particularly its low transaction throughput and long confirmation times, which stem from its Nakamoto Consensus protocol. The authors analyze the security implications of increasing the block rate and decreasing the block interval in Bitcoin's Proof-of-Work system. They propose the Greedy Heaviest Observed Subtree (GHOST) protocol as an alternative chain selection rule. GHOST allows for a higher block rate by including 'stale' blocks (blocks that are mined but not part of the longest chain) in the calculation of the heaviest chain. This modification aims to reduce incentives for selfish mining and maintain security guarantees even with increased block rates. The core contribution is demonstrating how GHOST can potentially enable significantly higher transaction throughput and faster confirmation times for Bitcoin-like cryptocurrencies without compromising the system's security against adversaries controlling a substantial portion of the mining power. This research was foundational for later discussions on Proof-of-Work scalability.