對等檔案分享系統的分散式控制

Abstract

同儕計算(Peer-to-Peer,P2P)是一種通訊模式，在P2P系統中的使用者，每個人擁有相同的能力而且通訊中的任一方都可以初始化建立溝通橋樑，和它對比的模式包含了主從架構。目前P2P檔案分享已經成為了主要的P2P應用，它讓使用者們能夠互相合作地、搜尋、取得檔案。雖然P2P檔案分享系統能有效且穩定的提供可調整和自我組織的檔案服務，但是也因為它天生的分散性，使得在控制分享檔案的散佈這方面困難重重。在本論文裡，建議了一種分散式控制系統，能對符合檔案限制的使用者，限制他們的檔案分享。擁有檔案的使用者有責任去判斷要求檔案者的資格，且評估結果然後包進憑證裡，憑證由擁有檔案的使用者簽章然後交換。擁有憑證的使用者證明他符合資格 。

Peer-to-peer (P2P) is a communications model in which each party has the same capabilities and either party can initiate a communication session. Other models with which it might be contrasted include the client/server model and the master/slave model. P2P file sharing has been a major P2P application, and enables peers to distribute, search, and retrieve files collaboratively. Although P2P file sharing systems offer scalable and self-organized file services with wide availability and good stability, but the decentralized nature make them inherently difficult to control the distribution of shared files. In this thesis, a distribution control system is proposed to restrict the sharing of files to the peers who qualified the constraints associated with the files. Peers are responsible to gauge requesting peers’ qualifications for the files they are holding, and evaluation results are encapsulated in credentials signed and exchanged in the process. Credentials are collected and presented by peers as evidence of qualifications.