NeTS: Small: Collaborative Research: ReDS: Reputation for Directory Services in P2P Systems

对等(P2P)系统对于从通信到互联网上的内容递送的各种应用正变得越来越流行和重要。由于此类系统本质上是由大量不受信任的对等点组成的，因此系统中的恶意对等点可能会对它们的安全性和可靠性造成不利影响。特别是，P2P系统必须提供可靠的分散目录服务，以定位具有所需内容和服务的对等点。如果恶意对等点能够破坏目录查找，则系统的完整性将受到极大损害。该项目通过在目录级别应用信誉信息来提高后续查找的成功率，从而提高了P2P安全和可靠性方面的最新水平。新系统将使用来自成功和失败查找的信息以及对等系统的结构来获取各种对等点的声誉信息，并估计系统中恶意节点的位置。该项目还将包括对限制Sybil攻击的机制的调查，在Sybil攻击中，攻击者试图用恶意同行淹没系统。这些机制将社交网络链接的使用与P2P系统的结构相结合，为节点创建一个健壮的标识空间，从而限制系统中可以引入多少Sybils。通过这些技术的结合，该项目将使P2P系统更值得信赖和可靠，直接影响到目前已经使用此类系统的数百万用户。

Peer-to-peer (P2P) systems are gaining popularity and importance for applications ranging from communications to content delivery over the Internet. Since such systems are inherently formed by a large collection of untrusted peers, their security and reliability can be adversely impacted by malicious peers in the system. In particular, P2P systems must provide a reliable decentralized directory service for locating peers with the desired content and services. If malicious peers are able to subvert directory lookups, the integrity of the system is greatly compromised. This project advances the state of the art in P2P security and reliability by applying reputation information at the directory level for improved success of subsequent lookups. The new systems will use information from successful and failed lookups, as well as the structure of the peer-to-peer system, to derive reputation information for various peers and estimate the locations of malicious nodes in the system. The project will also include an investigation into mechanisms to limit Sybil attacks, in which attackers attempt to overwhelm the system with malicious peers. The mechanisms will combine the use of social network links and the structure of the P2P system to create a robust identifier space for nodes, thus constraining how many Sybils can be introduced into the system. Through a combination of such techniques, the project will make P2P systems more trustworthy and reliable, directly impacting the millions of users who already make use of such systems today.