Sybil attacks, in which an adversary forges a potentially unbounded number of identities, are a danger to distributed systems and online social networks. The goal of sybil defense is to accurately identify sybil identities. This paper surveys the evolution of sybil defense protocols that leverage the structural properties of the social graph underlying a distributed system to identify sybil ide...

Sybil attacks are becoming increasingly widespread, and pose a significant threat to online social systems; a single adversary can inject multiple colluding identities in the system to compromise security and privacy. Recent works have leveraged the use of social network-based trust relationships to defend against Sybil attacks. However, existing defenses are based on oversimplified assumptions...

Vehicular Ad-hoc Network (VANET) is vulnerable to many security threats including Sybil attack due to its open infrastructure. In this paper we have proposed a scheme to detect Sybil attacks using Digital Signature. The infrastructure needed includes vehicles, Road Side Units (RSUs) and Department of Motor Vehicle (DMV). In Sybil attack the malicious node, called Sybil attacker, illegally claim...

The Wormhole attack is a critical and challenging security threat for wireless sensor networks (WSNs). Although launching a wormhole attack is a relatively trivial task for the attacker, detecting it from an infected WSN is a tough job, because it can be launched from a compromised legitimate node. In recent years, signal processing methods, like the short term Fourier transform (STFT) and wave...

Wireless sensor networks are now widely used in many areas, such as military, environmental, health and commercial applications. In these environments, security issues are extremely important since a successful attack can cause great damage, even threatening human life. However, due to the open nature of wireless communication, WSNs are liable to be threatened by various attacks, especially des...

Preventing Collaborative Wormhole Attacks on AODV-Based Mobile Ad Hoc Networks c ©Vincent Koo, 2012 Master of Science Computer Science Ryerson University Due to recent advances in wireless communication technologies, mobile ad hoc networks (MANETs) have become the networks of choice for use in various applications. Unfortunately, this advantage comes with serious security concerns, particularly...

We describe two techniques for reducing the effectiveness of sybil attacks, in which an attacker uses a large number of fake user accounts to increase his reputation. The first technique uses a novel transformation of the ranks returned by the PageRank system. This transformation not only reduces susceptibility to sybil attacks but also provides an intuitive and easily interpreted reputation sc...

Wireless sensor networks can be deployed in inhospitable terrains or in hostile environments to provide continuous monitoring and processing capabilities. Due to the wireless and distributed nature, security is very crucial issue in wireless sensor network. Security comes from attacks. Detecting wormhole attack is very hard compared to other attacks because it uses private, out-of-band channel ...

Internet protocols permit a single machine to masquerade as many, allowing an adversary to appear to control more nodes than it actually does. The possibility of such Sybil attacks has been taken to mean that distributed algorithms that tolerate only a fixed fraction of faulty nodes are not useful in peer-to-peer systems unless identities can be verified externally. The present work argues agai...

Ad-hoc networks are talented but are exposed to the risk of wormhole attacks. However, a wormhole attack can be mounted easily and forms stern menaces in networks, particularly against various ad-hoc wireless networks. The Wormhole attack distorts the network topology and decrease the network systems performance. Therefore, identifying the possibility of wormhole attacks and recognizing techniq...