A survey of techniques to prevent sybil attacks

Any decentralized, distributed network isvulnerable to the Sybil attack wherein a malicious node masquerade as several different nodes, called Sybil nodes disrupting the proper functioning of the network. A Sybil attacker can create more than one identity on a single physical device in order to launch a coordinated attack on the network or can switch identities in order to weaken the detection process, thus promoting lack of accountability in the network. In this paper, different types of Sybil attacks, including those occurring in peer-to-peer reputation systems, self-organizing networks and social network systems are discussed. Also, various methods that have been suggested over time to decrease or eliminate their risk completely are also analysed.