Traditionally, peer-to-peer systems have relied on altruism and reciprocity. Although incentive-based models have gained prominence in new-generation peer-to-peer systems, it is essential to recognize the continued importance of cooperative principles in achieving performance, fairness, and correctness. The lack of this acknowledgment has paved the way for selfish peers to gain unfair advantages in these systems. As such, we address the challenge of selfish peers by devising a mechanism to reward sustained cooperation. Instead of relying on global accountability mechanisms, we propose a protocol that naturally aggregates local evaluations of cooperation. Traditional mechanisms are often vulnerable to Sybil and misreporting attacks. However, our approach overcomes these issues by limiting the benefits selfish peers can gain without incurring any cost. The viability of our algorithm is proven with a deployment to 27,259 Internet users and a realistic simulation of a blockchain gossip protocol. We show that our protocol sustains cooperation even in the presence of a majority of selfish peers while incurring only negligible overhead.

翻译：传统上，点对点系统依赖于利他主义和互惠原则。尽管基于激励的模型在新一代点对点系统中日益受到重视，但认识到合作原则在实现性能、公平性和正确性方面的持续重要性至关重要。对此缺乏认知为自私节点在这些系统中获取不公平优势铺平了道路。为此，我们通过设计一种奖励持续合作的机制来应对自私节点带来的挑战。我们不依赖全局问责机制，而是提出一种能自然聚合局部合作评估的协议。传统机制通常容易遭受女巫攻击和虚假报告攻击。然而，我们的方法通过限制自私节点在不付出任何成本的情况下所能获得的收益来克服这些问题。该算法的可行性已通过面向27,259名互联网用户的部署以及区块链八卦协议的真实仿真得到验证。我们证明，即使在自私节点占多数的环境中，该协议仍能维持合作，且仅产生可忽略的开销。