关键词: 区块链, PoW共识机制, 公地悲剧, 门限密码, 保证金模型

Abstract: Aiming at the huge resource consumption, the bottleneck of the system performance and “tragedy of the commons” in the PoW(proof of work) consensus mechanism of bitcoin, we analyze the “tragedy of the commons” caused by only transaction fees rewarding in the later stage of the bitcoin system from the perspective of game theory and propose a consensus mechanism based on threshold cryptography (TCCM) in this paper. Firstly, the new consensus protocol introduces the idea of margin, and proposes a margin model based on threshold group signature theory. The model not only ensures the security of the margin, but also provides a guarantee for the node to honestly produce the block. Secondly, a bidding model of the right of accounting is also constructed using the idea of threshold encryption to generate a node that can produce the block. This model can guarantee the fairness of the bidding model environment and select the accounting node randomly. Then, a new incentive mechanism is redesigned based on the original block rewards so that more nodes can participate in the consensus process. Finally, the results of security and performance analysis show that TCCM not only effectively reduces the huge resource consumption, but also improves the transaction processing efficiency and makes the whole blockchain system more secure.

Key words: blockchain, PoW consensus mechanism, tragedy of the commons, threshold cryptography, margin model