在對等式網路下植基於群體遞移性與節點分類性之安全信任系統

Abstract

由於其服務使用者是採用非集中式的架構，已使得點對點(Peer-to-peer, P2P)的系統廣泛地被使用在現今實際的網路上，不過此開放與匿名式的系統環境其隱含的問題是易於遭受攻擊。一個信任系統是解決此惡意攻擊問題的方法，然而此信任系統必須是植基於一些規則且提供強健與完整的設計，以使得攻擊者不易攻擊與傷害此信任系統，並且可鼓勵誠實參與者加入此系統。 在本論文中，我們提出一個植基於群體遞移的安全信任系統，其中每一個要求者與提供者是利用其信任度與在此系統的參與度而所決定。整個網路被區分為幾個區域，每一個區域存在一個管理者負責管理存取點(peer)對其他存取點的存取授權。在不同的存取點(peer)間以及不同的管理者間之交易是採用不同的協定以滿足其不同的交易性質。在本系統中我們採用一種稱為Simple Distributed Security Infrastructure (SDSI)的自我驗證 ( self-certification)的憑證系統以達成交易簽章與代表在此網路下各個存取點的身份 。 我們相信此種沒有貢獻就沒有服務的信任系統將適用於現今的點對點網路系統。

Peer-to-peer (P2P) systems are gaining a wide popularity in actual networks, due to their decentralized structure in offering services to users. The inherent problem of such an open and anonymous environment is its weakness to attackers. A reputation system is believed to be a solution to alleviate or even stop malicious peers from harming the system. However, this reputation system should be strong enough, well designed and based on certain rules to discourage attackers and inject trust and incentives to participation into the system.

In this paper, we propose a secure reputation system based on group transitivity where every requester and provider is selected according to her reputation and participation in the community service. The network is organized by area, each having a manager responsible for handling its peers' access to other groups' peers. In every area the transactions between the different peers and Area Managers are insured through different protocols that we designed for this purpose. A self-certification generating a Simple Distributed Security Infrastructure (SDSI) certificate is used for each transaction's signature and uniquely identifies every peer in the network. We believe that this kind of reputation system where no contribution results in no service will have its domain of application in the large world of P2P network.