Sybil Limit: A Near-Optimal Social Network Defense Against Sybil Attacks

Abstract

Open-access distributed systems such as peer-to-peer systems are particularly vulnerable to sybil attacks, where a malicious user creates multiple fake identities (called sybil nodes). Without a trusted central authority that can tie identities to real human beings, defending against sybil attacks is quite challenging.Among the small number of decentralized approaches, our recent SybilGuard protocol leverages a key insight on social networks to bound the number of sybil nodes accepted. Despite its promising direction, SybilGuard can allow a large number of sybil nodes to be accepted. Furthermore, SybilGuard assumes that social networks are fast-mixing, which has never been confirmed in the real world. This paper presents the novel SybilLimit protocol that leverages the same insight as SybilGuard, but offers dramatically improved and near-optimal guarantees. The number of sybil nodes accepted is reduced by a factor of  around 200 times in our experiments for a million-node system. We further prove that SybilLimit’s guarantee is at most a  factor away from optimal when considering approaches based on fast-mixing social networks. Finally, based on three large-scale real-world social networks, we provide the first evidence that real-world social networks are indeed fast-mixing. This validates the fundamental assumption behind SybilLimit’s and SybilGuard’s approach.

Existing system:

Sybil attack means use others IP address for our communication. It create major problem in the network. In Existing system Packets are filter by using Distributed Packet filtering method used here. Denial of service (DOS) attack is major issue in the network, this attack create confuse while detecting attacker. Inter domain ip spoofing can’t detecting here. Because source router do the detecting work based on the source router connection, if attacker use address of some other system which using same source router for reaching destination that’s why problem for finding attacker. 

 

Proposed System:

In Proposed system, route-based packet filters method. Each node has individual path for deatination.It detected by using Sybil Guard System. It determine the path of node name which  inside in the Packet header. This path also append with packet header. Packet filter  take decision for pass packet or discard packets. So inter domain Sybil attack  avoid by using this method. Find out the Sybil node and maintain in separate monitoring table in Sybil guard system.

 

System Requirements:

SOFTWARE REQUIREMENTS

n  Language : Java, swing

n  Back End Tool: SQL SERVER 2000

n  Operating System: Windows 98 and more.

HARDWARE REQUIREMENTS

n  Processor : Intel Pentium III Processor 

n  Random Memory: 128MB

n  Hard Disk :20GB