Sharif Digital Repository

In this work we have examined the problem of consensus information fusion from a novel point of view, challenging the fundamental assumption of mutual trust among the fusion parties. In quest for a method to make information fusion possible while preserving the mutual confidentiality and anonymity of the fused information even in case of collusion of the malicious nodes, we propose the Blind Information Fusion Framework (BIFF). In BIFF, which is a secure information fusion framework, the nodes are not aware of the actual information they are processing, yet converging to the intended result(s). We formulate BIFF according to the anonymization transform and discuss its robustness against... 

Sharding, i.e. splitting the miners or validators to form and run several subchains in parallel, is known as one of the main solutions to the scalability problems of blockchains. The drawback is that as the number of miners expanding each subchain becomes small, it becomes vulnerable to security attacks. To solve this problem, a framework, named as Ployshard, has been proposed in which each validator verifies a coded combination of the blocks introduced by different subchains, thus helping to protect the security of all subchains. In this paper, we introduce an attack on Ployshard, called the discrepancy attack, which is the result of malicious nodes controlling a few subchains and... 

Cooperation among nodes is important in ad hoc networks since in such networks nodes depend on each other for forwarding packets. However, cooperation in such operations consumes nodes energy and recourses. Therefore, it is necessary to design incentive mechanisms to enforce nodes to forward packets when the source and destination of the packet are other nodes in the network. We study routing in ad hoc and wireless networks from a game theoretic view point. Based on this view, the network consists of selfish and greedy nodes who accept payments for forwarding data for other nodes if the payments cover their individual costs incurred by forwarding data. Also, route falsification attacks are... 

This research aims to represent a novel approach to detect malicious nodes in Ad-hoc On-demand Distance Vector (AODV) within the next-generation smart cities. Smart city applications have a critical role in improving public services quality, and security is their main weakness. Hence, a systematic multidimensional approach is required for data storage and security. Routing attacks, especially sinkholes, can direct the network data to an attacker and can also disrupt the network equipment. Communications need to be with integrity, confidentiality, and authentication. So, the smart city and urban Internet of Things (IoT) network, must be secure, and the data exchanged across the network must... 

Wireless ad hoc networks are vulnerable against many types of attacks including black hole. In this paper we investigate the effect of this attack on ad hoc networks. Furthermore, we use hash chain to prevent this type of attack in a network that uses AODV as a routing protocol and results of applying this method has been investigated. Simulation results using OPNET simulator indicates that packet delivery ratio, in the presence of malicious nodes, reduces remarkably and proposed approach can prevent the effect of black hole attacks  

Cooperation among nodes is vital in wireless networks since in such networks nodes depend on each other for routing packets. However, cooperation in such operations consumes nodes recourses such as battery and bandwidth. Therefore, it is necessary to design incentive mechanisms to enforce nodes to forward packets when the source and destination of the packet are other nodes. We study routing in wireless networks from a game theoretic view point. Based on this view, the network consists of greedy and selfish nodes who accept payments for forwarding data for other nodes if the payments cover their individual costs incurred by forwarding data. Also, route falsification attacks are easy to... 

Cooperation among nodes is vital in Mobil Ac Hoc Networks (MANETs) since in such networks nodes depend on each other for forwarding and routing packets. However, cooperation in such operations consumes nodes' recourses such as battery and bandwidth. Therefore it is necessary to design incentive mechanisms to enforce nodes to forward packets when the source and destination of the packet are other nodes. In this paper, we present a distributed fair solution to judge, punish and re-admit a selfish node, forcing nodes to cooperate with each other. Our scheme is different from previous ones in that it combines two characteristics that have been separately handled in previous works. The first... 

Performance of routing is severely degraded when misbehaving nodes drop packets instead of properly forwarding them. In this paper, we propose a Game-Theoretic Adaptive Multipath Routing (GTAMR) protocol to detect and punish selfish or malicious nodes which try to drop information packets in routing phase and defend against collaborative attacks in which nodes try to disrupt communication or save their power. Our proposed algorithm outranks previous schemes because it is resilient against attacks in which more than one node coordinate their misbehavior and can be used in networks which wireless nodes use directional antennas. We then propose a game theoretic strategy, ERTFT, for nodes to... 

Different attacks on routing protocols in ad hoc networks occur that one of the most dangerous types is called wormhole attack. This attack happens with the assistance of at least two or more malicious nodes. In this attack nodes create a private tunnel which if a packet comes to one of them, it will be guided to other pair of these malicious nodes by this tunnel and that node broadcasts it into network. This action provides a short connection in the network that is controlled by these malicious nodes. Hence they control all Packets that come to them and threaten the security of data within packets or delete them. Totally, what a wormhole does is an incorrect understanding of network... 

Different attacks on routing protocols in ad hoc networks occur that one of the most dangerous types is called wormhole attack. This attack happens with the assistance of at least two or more malicious nodes. In this attack nodes create a private tunnel which if a packet comes to one of them, it will be guided to other pair of these malicious nodes by this tunnel and that node broadcasts it into network. This action provides a short connection in the network that is controlled by these malicious nodes. Hence they control all Packets that come to them and threaten the security of data within packets or delete them. Totally, what a wormhole does is an incorrect understanding of network... 

Wireless sensor networks (WSNs) are a new technology, foreseen to be used increasingly in the near future, and security is an important issue for them. However because of the nodes resource limitations, other schemes proposed for securing general ad hoc networks, are not appropriate for WSNs. Usually some nodes act maliciously and they are able to do different kinds of DoS attacks. In order to make the network more secure, malicious nodes should be isolated from the network. In this paper, we model the interaction of nodes in WSN and intrusion detection system (IDS) as a Bayesian game formulation and use this idea to make a secure routing protocol. By this approach nodes are motivated to act... 

Mobile ad hoc networks have different characteristics from wired networks. There are new challenges related to security issues that need to be addressed. In this paper, first, critical nodes and authentication in mobile ad hoc networks are discussed. Then, a monitoring nodes selection method with high battery power in these networks is presented. We propose a three-phase detection scheme. In the first phase, unauthorized nodes and in the second phase, malicious nodes are detected. Finally in the third phase, nodes with the largest battery power as monitoring nodes are considered. In the first and the second phases, detection scheme uses non-interactive zero knowledge technique in order to... 

Locally multipath adaptive routing (LMAR) protocol, classified as a new reactive distance vector routing protocol for MANETs is proposed in this paper. LMAR can find an ad-hoc path without selfish nodes and wormholes using a random search algorithm in polynomial-time. Also when the primary path fails, it discovers an alternative safe path if network graph remains connected after eliminating selfish/malicious nodes. The main feature of LMAR to seek safe route free of selfish and malicious nodes in polynomial time is its searching algorithm and flooding stage that its generated traffic is equiloaded compared to single-path routing protocols but its ability to bypass the attacks is much better... 

Mobile Ad Hoc Networks (MANETs) are networks with selforganizing capabilities and without a fixed infrastructure. Wireless nodes communicate among themselves using multi-hop radio relaying, without requiring the packets to pass through a central access point or a base station. In a highly mobile and infrastructure-less scenario, pre-configuration of addresses is not possible. Therefore node addresses need to be configured dynamically with minimum delay and packet loss. Existing solutions for IP address auto-configuration do not address security issues. In this paper we propose a secure address autoconfiguration for Mobile Ad hoc Networks (MANET) based on Virtual Address Space Mapping [1]....