信任模型中搭便车节点的抑制

摘要

Although current existing trust model reduces the impact of peers' malicious attack in P2P system, these reputation systems do not concern with reducing free riders in P2P networks,namely, peers with high trust value tansform to free riders. Because lots of free riders exist,robust and avaliable of P2P system are degraded. So,a trust model based on time slots was designed,and the nearer time from now the greater time slot's weight was gaven. Theoretical analysis and simulation show that this proposal not only prevents peers with high trust value to free riders,but also limits peers to make malicious attack recently,and peers' trust value are more and more hight in compared with other proposals.%现有的信任机制虽然有效地遏制了P2P系统中节点的恶意攻击,但未考虑如何抑制内在的大量搭便车节点的存在,即高信任值节点向搭便车节点的转变.大量搭便车节点的存在,降低了P2P网络的健壮性及可用性,为此设计了基于时间窗口的信任模型,对距现在时刻越近的时间窗口给予的权重值越大.仿真结果表明,机制不仅能够有效抑制大量高信任值节点向搭便车节点的转变,而且与提出的其它方案相比,能够有效遏制节点近期内进行恶意攻击,并且节点的信任值会更高.