Peer-to-peer (P2P) networks are a cornerstone of modern computing, and their security is an active area of research. Many defenses with strong security guarantees have been proposed; however, the most-recent survey is over a decade old. This paper delivers an updated review of recent theoretical advances that address classic threats, such as the Sybil and routing attacks, while highlighting how emerging trends -- such as machine learning, social networks, and dynamic systems -- pose new challenges and drive novel solutions. We evaluate the strengths and weaknesses of these solutions and suggest directions for future research.

翻译：对等（P2P）网络是现代计算的基石，其安全性是一个活跃的研究领域。目前已提出许多具有强安全保证的防御机制；然而，最新的综述文献已有十余年历史。本文对近期的理论进展进行了更新综述，这些进展旨在应对经典威胁（如女巫攻击和路由攻击），同时重点阐述了新兴趋势——如机器学习、社交网络和动态系统——如何带来新的挑战并推动创新解决方案的产生。我们评估了这些解决方案的优势与不足，并指出了未来的研究方向。