An Effectual Secured Approach Against Sybil Attacks in Wireless Networks

Detecting Sybil attacks in wireless sensor networks using UWB ranging-based information

Mobile Ad hoc Networks (MANET) comprises of self-organizing autonomous mobile nodes. MANETs are open and decentralized. Therefore they are vulnerable to malicious entities. MANETs are multi-hop wireless network where all nodes supportively maintain network connectivity without a centralized infrastructure. Since MANETs are infrastructure less and independent, the secure communication is the main issue. Therefore they are vulnerable to malicious entities. Here the location identity and traffic can be traced out by an outside observer. Anonymity means secure communications by hiding node identities and preventing traffic analysis attacks by outside observers. This paper proposes Position based Anonymous Routing Scheme in MANETs (PARS).Here the routing is based on Greedy Perimeter Stateless Routing Protocol. The objective is an anonymous routing protocol for the network. The proposed one is a zone based anonymous GPSR based protocol that can provide source, destination and route anonymity. Performance of the proposed system is compared with that of GPSR and AODV using Network Simulator. Index Terms: Anonymous routing, position-based routing, random forwarder, zone partition. I. Introduction Mobile Ad hoc Networks are collection of independent mobile nodes that can communicate by radio waves. It is an infrastructure less self-organizing network. The nodes that are in radio range can communicate by single hop or by multi hop with the help of intermediate nodes. The network is open and decentralized and fully distributed. So they are perfect choice for communication and information sharing. MANETs are susceptible to malicious entities that aim to alter and analyzed the traffic analysis by communication eaves dropping or attacking routing protocols. MANETs are characterized by their distributed operation, multi hop routing, dynamic topology and shared physical medium. Nodes in a MANET are independently free to move in any direction. Due to the lack of a centralized coordinator security is the major concern here. Wireless communication can endure interferences or malicious interceptions; whereas multi-hop communication assumes that each node will perform properly its functions to support network services. Further, self-organization increases the complexity of security management operations as access control, node authentication, secure routing and cryptographic key distribution. There is no fixed infrastructure and the topology is frequently changing due to node mobility or environmental changes. Therefore, it is very hard to maintain a stable and efficient end-to-end route in an ad-hoc network. Each node in MANET is energy constrained. There is verylimited physical security in MANET. The type of attacks can be Active attacks or Passive attacks. The common security issues are Passive attacks which include eaves dropping and information disclosure. Active attacks include Do Sand Data modification. There are other more specific problems with mobile ad hoc network such as vulnerability of channels and nodes, Byzantine black hole and Byzantine wormhole attack. The security issue also includes attacks that may inject erroneous routing information and diverting network traffic thus making routing inefficient. There are many methods to reduce the impact of these attacks, which include a secure routing using public and private key s to get a certification authority and use of digital signatures and prior it rust relationships. Routing is the process of communication from one node to the other host in a network. Routing is the process off or warding packet towards its destination using most efficient path. Routing efficiency is measured in terms of Number of hops, traffic, security, etc. Routing protocols in MANETs are divided as reactive proactive and hybrid. Reactive Protocol maintains the routes in on demand manner. In route discovery phase it floods the route request (RREQ) packets throughout the network. Dynamic source Routing (DSR), ad hoc on- demand distance vector routing (AODV) are some of the examples of reactive protocols. In proactive approach every node in the MANET continuously maintains the complete routing information of the entire network. This is accomplished by flooding network periodically with network status information. Global State Routing (GSR), Hierarchical State Routing (HSR) and Destination Sequenced Distance Vector Routing (DSDV) are some of the examples of proactive

Wireless sensor networks have been widely applied in many areas due to their unique characteristics. These have exposed them to different types of active and passive attacks. In the literature, several solutions have been proposed to mitigate these attacks. Most of the proposed solutions are too complex to be implemented in wireless sensor networks considering the resource-constraint of sensor nodes. In this work, we proposed a hierarchical trust mechanism based on clustering approach to detect and prevent denial of service attacks in wireless sensor networks. The approach was validated through simulation using Network Simulator (NS2). The following metrics were used to evaluation the proposed scheme: packet delivery ratio, network lifetime, routing delay, overhead, and number of nodes. The proposed approach is capable of detecting compromised sensor nodes vulnerable to a denial of service attacks. Moreover, it is able to detect all sensed data that have been compromised during transmission to the base station. The results show that our method can effectively detect and defend against denial of service attacks in sensor wireless sensor networks.

The verifiable implicit asking is to speed up a certain feasible computation (e.g., y=x d mod n) based on a secret (d) stored in a relatively powerless device (called Client) with the help of powerful device(s) (called Server(s)) in such a way that Client can check the behavior of Server(s) and that the leakage of the secret to Server(s) should be suppressed as much as possible. Possible attacks to obtain Client's secret are classified into passive and active attacks. Passive attacks can be completely nullified by dividing the target computation into two parts so that one depends on d but the other does not and then by asking Server to do only the latter part. However since such a method brings relatively low speed-up performance, we discuss a method to obtain verifiable implicit asking protocols highly secure against passive attacks by modifying some base protocols which are fast enough but not completely free from passive attacks since sending to Server some information not independent from d.KeywordsSmart CardActive AttackTarget ComputationAddition ChainPassive AttackThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Game Theoretical Defense Mechanism Against Reputation Based Sybil Attacks

Many side channels including power consumption, electromagnetic emanation, optical radiation, and even sound have been studied since the first publication of a side channel attack at the end of the 1990s. Most of these channels can be relatively easily used for an overall analysis of the cryptographic system (implementation of efficient passive attacks) or for injection of faults. Until recently, only the optical channel allowed both analysis of locally leaked information and precise injection of faults (single-bit errors). Recent works showed that the near-field electromagnetic channel enables similar results to be obtained. Like the optical channel, the near-field electromagnetic channel allows both active and passive attacks, which, in addition, can be theoretically non-invasive and contactless. However, the cost of the attack bench that is needed to exploit the near-field electromagnetic channel is less than that of an optical channel. Recently, we showed that it is possible to use the near-field electromagnetic channel to perform an efficient active attack targeting the true random number generator (TRNG) based on ring oscillators. In cryptography, TRNGs are chiefly used to generate encryption keys and other critical security parameters, so the proposed active attack could have serious consequences for the security of the whole cryptographic system. Here, we present the coupling of a passive attack and an active attack. The proposed coupled attack first uses a spectral differential analysis of the TRNG electromagnetic radiation to obtain valuable information on the position of ring oscillators and their frequency range. This information is then used to tune the electromagnetic harmonic signal to temporarily synchronize the ring oscillators. In this paper, we propose a fault model of the entropy extractor which shows that the behavior of the ring oscillators changes, and that it occurs additional and unwanted “fake rising edges” of the clock signal which disturb the flip-flops involved in such TRNGs. The effectiveness of our proposed coupled attack questions the use of ring oscillators in the design of TRNGs.

A Wireless Sensor Network (WSN) is a wireless network consisting of small sensor nodes. Sensors are used to monitor physical or environmental conditions. WSNs are particularly used in military and civilian applications. As WSNs are generally deployed in an unattended area, they are prone to various types of attacks. One of the harmful attacks is Sybil attack in which a node illegitimately claims multiple identities. In this scenario, legitimate node shares data to the malicious node and the data are lost. So that it becomes necessary to secure the network from this type of attack. This paper aims to study, discuss and analyze the various techniques for detection of Sybil attack in Wireless Sensor Networks. Also various protocols affected by Sybil attack are studied and analyzed.

A type of ad hoc network formed among moving vehicles that come in one another’s radio transmission range is called Vehicular Ad Hoc Network (VANET). VANET may be deployed using three architectures: pure ad hoc, WLAN and hybrid. Vehicle to Vehicle (V2V) and Vehicle to Infrastructure (V2I) are the two modes in VANET used for communication among vehicles. These features not only distinguish a VANET from other ad hoc networks but also make these networks more exposed to attacks and increase their complexity. These networks being the primary mechanism for communication in VANETs, appropriate and timely delivery of information is of prime importance. Due to the existence of various vehicular traffic scenarios, a single category of routing protocols is not sufficient for the VANETs. Therefore, various categories of routing protocols have been tailored to meet specific kinds of routing requirements in this framework. Most significant ones are ad hoc/topology-based, position-based, geocast-based, cluster-based, broadcast-based protocols. There exist a number of attacks that apart from affecting various other parameters also affect the routing protocols in these VANETs. Most of these attacks may be launched in all the above-mentioned three architectures. But, one of the most dangerous attacks is the Sybil attack that may be initiated in pure ad hoc deployment of VANET where vehicles communicate with one another in one to one manner using carry forward approach. In this paper, with the help of illustrative example for each of the five categories of routing protocols, we show how Sybil attack affects these protocols. Considering the ad hoc scenarios in VANETs, we also discuss a prevention mechanism for the Sybil attack briefly.

In order to prevent the disclosure of privacy-sensitive data, such as names and relations between users, social network graphs have to be anonymised before publication. Naive anonymisation of social network graphs often consists in deleting all identifying information of the users, while maintaining the original graph structure. Various types of attacks on naively anonymised graphs have been developed. Active attacks form a special type of such privacy attacks, in which the adversary enrols a number of fake users, often called sybils, to the social network, allowing the adversary to create unique structural patterns later used to re-identify the sybil nodes and other users after anonymisation. Several studies have shown that adding a small amount of noise to the published graph already suffices to mitigate such active attacks. Consequently, active attacks have been dubbed a negligible threat to privacy-preserving social graph publication. In this paper, we argue that these studies unveil shortcomings of specific attacks, rather than inherent problems of active attacks as a general strategy. In order to support this claim, we develop the notion of a robust active attack, which is an active attack that is resilient to small perturbations of the social network graph. We formulate the design of robust active attacks as an optimisation problem and we give definitions of robustness for different stages of the active attack strategy. Moreover, we introduce various heuristics to achieve these notions of robustness and experimentally show that the new robust attacks are considerably more resilient than the original ones, while remaining at the same level of feasibility.

In this study, by exploiting the properties of finite‐length polar codes, the authors introduce a physical layer encryption scheme to make secure (from a computational security perspective) and efficient communication between a sender (Alice) and a legitimate receiver (Bob) against both active and passive attacks, simultaneously. To prevent active attacks, two techniques are considered: (i) a novel method is introduced to keep the generator matrix of polar code secret from an active attacker (Oscar); (ii) a proper joint polar encoding/encryption algorithm based on the hidden generator matrix is introduced. Two additional strategies are considered against passive attacks: (i) a new method is introduced to partition the bit‐channels into good and bad bit‐channels and then the scrambled information bits are transmitted over those bit‐channels that are good for Bob but bad for a passive attacker (Eve); (ii) the secret key cryptography is implemented at the physical layer, such that Eve cannot decode the eavesdropped data without the knowledge of the secret key shared between the authorised parties. Besides, this study discusses efficiency analysis results consisting key size, error performance and computational complexity of the proposed scheme.

Decentralized distributed systems such as peer-to-peer systems are particularly vulnerable to sybil attacks, where a malicious user pretends to have multiple identities (called sybil nodes). Without a trusted central authority, defending against sybil attacks is quite challenging. Among the small number of decentralized approaches, our recent SybilGuard protocol [H. Yu et al., 2006] leverages a key insight on social networks to bound the number of sybil nodes accepted. Although its direction is promising, 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 ominus(radicn), or around 200 times in our experiments for a million-node system. We further prove that SybilLimit's guarantee is at most a log n 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.

In wireless networks,the authenticity and uniqueness of node identities are essential to the fundamental operations such as routing, resource allocation, and intrusion detection. In this paper, we investigate Sybil attack, an attack in which a malicious node illegitimately acquires multiple identities and performs as these nodes simultaneously. We propose an effective approach to monitoring and detecting such attacks by integrating network security and visualization methods. The security component explores the time-varying network topology and its statistical and geometry information to detect the existence of Sybil attacks. The visualization component incorporates the detection results and provides an effective mechanism to illustrate abnormal topology patterns and locate fake identities. These two components are integrated into a practical system that takes advantage of both interactive visualization and intelligent security methods. Experimental studies are conducted to investigate the impacts of the network parameters such as node connectivity on the detection capability of the proposed mechanism.

Ad Hoc network often termed as an infrastructure-less, self- organized or spontaneous network.The execution and survival of an ad-hoc network is solely dependent upon the cooperative and trusting nature of its nodes. However, this naive dependency on intermediate nodes makes the ad-hoc network vulnerable to passive and active attacks by malicious nodes and cause inflict severe damage. A number of protocols have been developed to secure ad-hoc networks using cryptographic schemes, but all rely on the presence of trust authority. Due to mobility of nodes and limitation of resources in wireless network one interesting research area in MANET is routing. This paper offers various trust models and trust based routing protocols to improve the trustworthiness of the neighborhood.Thus it helps in selecting the most secure and trustworthy route from the available ones for the data transfer.KeywordsAd Hoc networkTrustSecurityTrust models

At Crypto’ 88, Matsumoto, Kato and Imai proposed a protocol, known as RSA-S1, in which a smart card computes an RSA signature, with the help of an untrusted powerful server. There exist two kinds of attacks against such protocols: passive attacks (where the server does not deviate from the protocol) and active attacks (where the server may return false values). Pfitzmann and Waidner presented at Eurocrypt ’92 a passive meet-in-the-middle attack and a few active attacks on RSAS1. They discussed two simple countermeasures to thwart such attacks: renewing the decomposition of the RSA private exponent, and checking the signature (in which case a small public exponent must be used). We present a new lattice-based provable passive attack on RSA-S1 which recovers the factorization of the RSA modulus when a very small public exponent is used, for many choices of the parameters. The first countermeasure does not prevent this attack because the attack is a one-round attack, that is, only a single execution of the protocol is required. Interestingly, Merkle and Werchner recently provided a security proof of RSA-S1 against one-round passive attacks in some generic model, even for parameters to which our attack provably applies. Thus, our result throws doubt on the real significance of security proofs in the generic model, at least for server-aided RSA protocols. We also present a simple analysis of a multi-round lattice-based passive attack proposed last year by Merkle.

For the intrinsic characteristics cause several vulnerabilities of MANET, anonymous routing protocol attracts much more attention in secure mobile ad hoc networks for the purposes of security and privacy concerns. Until recently, lots of anonymous routing protocols have been proposed. However, most of them are single path or use one path at a time or can not thwart both the passive attacks and active attacks simultaneously. Thus, we propose an anonymous multipath routing protocol based on secret sharing. The protocol provides identity anonymity, location anonymity, data and traffic anonymity based on cryptograph technology and secret sharing in MANET communication. Meanwhile, we also introduce hash function to detect active attacks in our data transmission process. The protocol can effectively thwart the various passive attacks and reduce the successful probability of active attacks such as intercept and physical destroy attacks. In addition, Simulation results show that our scheme provides a reasonably good level of security and performance.