Mitigating Selfish Behavior in Mobile Ad Hoc Networks: A Survey
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paper_title: Nuglets: a Virtual Currency to Stimulate Cooperation in Self-Organized Mobile Ad Hoc Networks

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In mobile ad hoc networks, it is usually assumed that all the nodes belong to the same authority; therefore, they are expected to cooperate in order to support the basic functions of the network such as routing. In this paper, we consider the case in which each node is its own authority and tries to maximize the benefits it gets from the network. In order to stimulate cooperation, we introduce a virtual currency and detail the way it can be protected against theft and forgery. We show that this mechanism fulfills our expectations without significantly decreasing the performance of the network.
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paper_title: Stimulating Cooperation in Self-Organizing Mobile Ad Hoc Networks

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In military and rescue applications of mobile ad hoc networks, all the nodes belong to the same authority; therefore, they are motivated to cooperate in order to support the basic functions of the network. In this paper, we consider the case when each node is its own authority and tries to maximize the benefits it gets from the network. More precisely, we assume that the nodes are not willing to forward packets for the benefit of other nodes. This problem may arise in civilian applications of mobile ad hoc networks. In order to stimulate the nodes for packet forwarding, we propose a simple mechanism based on a counter in each node. We study the behavior of the proposed mechanism analytically and by means of simulations, and detail the way in which it could be protected against misuse.
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paper_title: Sprite: a simple, cheat-proof, credit-based system for mobile ad-hoc networks

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Mobile ad hoc networking has been an active research area for several years. How to stimulate cooperation among selfish mobile nodes, however, is not well addressed yet. In this paper, we propose Sprite, a simple, cheat-proof, credit-based system for stimulating cooperation among selfish nodes in mobile ad hoc networks. Our system provides incentive for mobile nodes to cooperate and report actions honestly. Compared with previous approaches, our system does not require any tamper-proof hardware at any node. Furthermore, we present a formal model of our system and prove its properties. Evaluations of a prototype implementation show that the overhead of our system is small. Simulations and analysis show that mobile nodes can cooperate and forward each other's messages, unless the resource of each node is extremely low.
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paper_title: Mitigating routing misbehavior in mobile ad hoc networks

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This paper describes two techniques that improve throughput in an ad hoc network in the presence of nodes that agree to forward packets but fail to do so. To mitigate this problem, we propose categorizing nodes based upon their dynamically measured behavior. We use a watchdog that identifies misbehaving nodes and a pathrater that helps routing protocols avoid these nodes. Through simulation we evaluate watchdog and pathrater using packet throughput, percentage of overhead (routing) transmissions, and the accuracy of misbehaving node detection. When used together in a network with moderate mobility, the two techniques increase throughput by 17% in the presence of 40% misbehaving nodes, while increasing the percentage of overhead transmissions from the standard routing protocol's 9% to 17%. During extreme mobility, watchdog and pathrater can increase network throughput by 27%, while increasing the overhead transmissions from the standard routing protocol's 12% to 24%.
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paper_title: CORE: A Collaborative Reputation Mechanism to enforce node cooperation in Mobile Ad hoc Networks

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Countermeasures for node misbehavior and selfishness are mandatory requirements in MANET. Selfishness that causes lack of node activity cannot be solved by classical security means that aim at verifying the correctness and integrity of an operation. We suggest a generic mechanism based on reputation to enforce cooperation among the nodes of a MANET to prevent selfish behavior. Each network entity keeps track of other entities’ collaboration using a technique called reputation. The reputation is calculated based on various types of information on each entity’s rate of collaboration. Since there is no incentive for a node to maliciously spread negative information about other nodes, simple denial of service attacks using the collaboration technique itself are prevented. The generic mechanism can be smoothly extended to basic network functions with little impact on existing protocols.
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paper_title: SORI: a secure and objective reputation-based incentive scheme for ad-hoc networks

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In an ad-hoc network, intermediate nodes on a communication path are expected to forward packets of other nodes so that the mobile nodes can communicate beyond their wireless transmission range. However, because wireless mobile nodes are usually constrained by limited power and computation resources, a selfish node may be unwilling to spend its resources in forwarding packets which are not of its direct interest, even though it expects other nodes to forward its packets to the destination. It has been shown that the presence of such selfish nodes degrades the overall performance of a non-cooperative ad hoc network. To address this problem, we propose a secure and objective reputation-based incentive (SORI) scheme to encourage packet forwarding and discipline selfish behavior. Different from the existing schemes, under our approach, the reputation of a node is quantified by objective measures, and the propagation of reputation is efficiently secured by a one-way-hash-chain-based authentication scheme. Armed with the reputation-based mechanism, we design a punishment scheme to penalize selfish nodes. The experimental results show that the proposed scheme can successfully identify selfish nodes and punish them accordingly.
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paper_title: Friends and foes: preventing selfishness in open mobile ad hoc networks

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Technological advances are leveraging the widespread deployment of mobile ad hoc networks. An interesting characteristic of ad hoc networks is their self-organization and their dependence of the behavior of individual nodes. Until recently, most research on ad hoc networks has assumed that all nodes were cooperative. This assumption is no longer valid in spontaneous networks formed by individuals with diverse goals and interests. In such environment, the presence of selfish nodes may degrade significantly the performance of the ad hoc network. This paper proposes a novel algorithm that aims to discourage selfish behavior in mobile ad hoc networks.
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paper_title: Self-policing mobile ad hoc networks by reputation systems

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Node misbehavior due to selfish or malicious reasons or faulty nodes can significantly degrade the performance of mobile ad hoc networks. To cope with misbehavior in such self-organized networks, nodes need to be able to automatically adapt their strategy to changing levels of cooperation. Existing approaches such as economic incentives or secure routing by cryptography alleviate some of the problems, but not all. We describe the use of a self-policing mechanism based on reputation to enable mobile ad hoc networks to keep functioning despite the presence of misbehaving nodes. The reputation system in all nodes makes them detect misbehavior locally by observation and use of second-hand information. Once a misbehaving node is detected it is automatically isolated from the network. We classify the features of such reputation systems and describe possible implementations of each of them. We explain in particular how it is possible to use second-hand information while mitigating contamination by spurious ratings.
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paper_title: On eliminating packet droppers in MANET: A modular solution

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In this paper we deal with misbehaving nodes in mobile ad hoc networks (MANETs) that drop packets supposed to be relayed, whose purpose may be either saving their resources or launching a DoS attack. We propose a new solution to monitor, detect, and safely isolate such misbehaving nodes, structured around five modules: (i) The monitor, responsible for controlling the forwarding of packets, (ii) the detector, which is in charge of detecting the misbehaving of monitored nodes, (iii) the isolator, basically responsible for isolating misbehaving nodes detected by the detector, (iv) the investigator, which investigates accusations before testifying when the node has not enough experience with the accused, and (v) finally the witness module that responds to witness requests of the isolator. These modules are based on new approaches, aiming at improving the efficiency in detecting and isolating misbehaving nodes with a minimum overhead. We describe these modules in details, and their interactions as well. We also mathematically analyze our solution and assess its performance by simulation, and compare it with the watchdog, which is a monitoring technique employed by almost all the current solutions.
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paper_title: OMH: suppressing selfish behavior in ad hoc networks with One More Hop

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In ad hoc networks, wireless nodes rely on each other to transmit data over multi-hops by forwarding packets. A selfish node may decide not to forward packets for other nodes to save its own resource but still use the network to send and receive data. Such a selfish behavior can degrade network performance significantly. Most existing work took observation, reputation and token based mechanisms. However observation based mechanism suffers from mobility and collusion; reputation and token based mechanisms suffer from system complexity and efficiency. In this paper, we propose One More Hop (OMH) protocol which suppresses selfish behavior from a totally new angle. Basing on the fact that the selfish but rational nodes still want to receive and send packets, if a node can not determine whether a packet is destined for it or not, it can not drop the packet. With modified routing protocol and cryptographic techniques, OMH achieves this design target. It is robust and efficient. The simulation shows that OMH works well under different network situations.
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paper_title: ICARUS: hybrId inCentive mechAnism for coopeRation stimUlation in ad hoc networkS

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Mobile ad hoc networks rely on the cooperation of nodes for routing and forwarding. However, individual nodes may not always be willing to cooperate. In order thus to stimulate cooperation in ad hoc networks, several incentive mechanisms have been developed. In this paper we propose a new hybrid incentive mechanism, called ICARUS, which is an extension of DARWIN, a well-known reputation-based mechanism, combining advantages of both reputation-based and credit-based mechanisms. The objective of ICARUS is to detect and punish selfish nodes efficiently and at the same time motivate nodes to cooperate by rewarding the packet forwarding. Furthermore, ICARUS ensures fairness for distant nodes and prevents selfish nodes from corrupting the system using false information. The proposed scheme's performance is tested through extended series of simulations and is compared with DARWIN. We show that ICARUS detects and isolates selfish nodes much faster, while at the same time improves the Quality of Service (QoS) received by non-selfish nodes, including distant ones.
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paper_title: Fighting against packet dropping misbehavior in multi-hop wireless ad hoc networks

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In multi-hop wireless ad hoc networks, the packets are forwarded through intermediate nodes along the source-destination path. Without having any control on packets forwarding, an intermediate node can behave selfishly or maliciously to drop packets going through it. The dropper motivation is the preservation of its resources, like its limited energy (selfish behavior) or the launch of denial of service attack (malicious behavior). In this paper, we propose an approach to verify the correct forwarding of packets by an intermediate node. The Merkle tree principle has been used for implementation in justification of our proposed approach. Through simulation, we have shown our approach efficiency, and we have evaluated its performance in both proactive and reactive routing protocol in ad hoc network. Also, we have compared our approach with the watchdog and the 2-hop ACK which are well-known approaches in the literature.
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Title: Mitigating Selfish Behavior in Mobile Ad Hoc Networks: A Survey

Section 1: INTRODUCTION
Description 1: Provide an overview of Mobile Ad Hoc Networks (MANETs), their applications, inherent characteristics, and the types of security threats they face, focusing on both passive and active attacks, including eavesdropping and packet dropping.

Section 2: MITIGATING SELFISH BEHAVIOR
Description 2: Discuss the various methods proposed to combat selfish behavior in MANETs, categorized into Incentive-Based Mechanisms, Reputation-Based Mechanisms, and other mechanisms.

Section 3: Virtual Currency
Description 3: Explore the nuglets mechanism, detailing the Packet Purse Model (PPM), Packet Trade Model (PTM), and the hybrid solution, and their implications for packet forwarding.

Section 4: Stimulating Cooperation
Description 4: Analyze approaches that stimulate cooperation among nodes, such as the tamper-resistant hardware-based method proposed by L. Buttyan and the Sprite system.

Section 5: Secure Incentive Protocol
Description 5: Describe the Secure Incentive Protocol (SIP), its session initialization, session-key establishment, and rewarding mechanisms.

Section 6: FESCIM
Description 6: Examine the Fair, Efficient, and Secure Cooperation Incentive Mechanism (FESCIM) and its impact on improving network performance and fairness.

Section 7: Watchdog and Pathrater
Description 7: Detail the watchdog mechanism and pathrater proposed by Sergio Marti et al., including their implementation and limitations.

Section 8: CORE
Description 8: Discuss CORE, a generic reputation-based mechanism, and its components such as the reputation table and watchdog mechanism.

Section 9: CONFIDANT
Description 9: Introduce the CONFIDANT protocol, its components, and how it handles misbehavior using trust and ALARM messages.

Section 10: SORI
Description 10: Outline the Secure and Objective Reputation-based Incentive (SORI) framework and its unique features for encouraging packet forwarding and punishing selfish behavior.

Section 11: Reputation-Based Mechanisms
Description 11: Describe reputation-based mechanisms proposed for detecting and isolating selfish nodes, focusing on various reputation functions like DDSIR, HAFS, and REP.

Section 12: Friends and Foes
Description 12: Explore the Friends and Foes algorithm that discourages selfish behavior by managing relationships among nodes.

Section 13: Self-Policing Mobile Ad Hoc Networks by Reputation Systems
Description 13: Explain self-policing mechanisms using reputation systems to detect and isolate misbehaving nodes.

Section 14: On Eliminating Packet Droppers in MANETs
Description 14: Present a solution to monitor, detect, and safely isolate misbehaving nodes using modules like monitor, detector, and isolator.

Section 15: An Acknowledgement-Based Approach
Description 15: Discuss the 2ACK scheme, its implementation with DSR protocol, and its impact on mitigating misbehavior in packet forwarding.

Section 16: Stimulating Node Cooperation in MANETs
Description 16: Examine combined mechanisms of reputation and incentive systems for stimulating node cooperation in MANETs.

Section 17: One More Hop
Description 17: Describe the One More Hop protocol, its longer path mechanism, and how it suppresses selfish behavior.

Section 18: COFFEE Protocol
Description 18: Discuss the context-free COFFEE protocol and how it stimulates packet forwarding without identifying selfish nodes.

Section 19: ICARUS
Description 19: Analyze the hybrid mechanism of ICARUS, its dual approach in rewarding cooperation and punishing selfishness.

Section 20: Fighting Against Packet Dropping
Description 20: Outline the method utilizing merkle tree principles to verify packet forwarding correctness and eliminate routes with packet droppers.

Section 21: CONCLUSION
Description 21: Summarize the survey, highlighting the classification of contributions into incentive-based, reputation-based, and other mechanisms, and the need for a novel method to mitigate selfish misbehavior in MANETs effectively.