Decentralized Reputation System Research Articles

A Survey on Reputation Systems for UAV Networks

The proliferation of unmanned aerial vehicle (UAV) networks is increasing, driven by their capacity to deliver automated services tailored to the varied demands of numerous smart city applications. Trust, security, and privacy remain paramount in the public domain. Traditional centralized network designs fall short of ensuring device authentication, data integrity, and privacy within the highly dynamic and adaptable environments of UAV networks. Decentralized reputation systems have emerged as a promising solution for enhancing the reliability and trustworthiness of data and communications within these networks while safeguarding UAV security. This paper presents an exhaustive survey of trust and reputation systems, exploring existing frameworks and proposed innovations alongside their inherent challenges. The crucial role of reputation systems is to strengthen trust, security, and privacy throughout these networks, and various strategies can be incorporated to mitigate existing vulnerabilities. As a useful resource for researchers and practitioners seeking to advance the state of the art in UAV network security, we hope this survey will spark further community discussion and stimulate innovative ideas in this burgeoning field.

Dynamic Decentralized Reputation System from Blockchain and Secure Multiparty Computation

In decentralized environments, such as mobile ad hoc networks (MANETs) and wireless sensor networks (WSNs), traditional reputation management systems are not viable due to their dependence on a central authority that is both accessible and trustworthy for all participants. This is particularly challenging in light of the dynamic nature of these networks. To overcome these limitations, our proposed solution utilizes blockchain technology to maintain global reputation information while remaining fully decentralized, and to secure multiparty computation to ensure privacy. Our system is not limited to specific settings, such as buyer/seller or provider/client scenarios, where only a subset of the network are raters while the others are ratees. Instead, it allows all nodes to participate in both rating and being rated. In terms of security, the system maintains feedback privacy in the semi-honest model, even in the presence of up to n−2 dishonest parties, while requiring only O(n) messages and having an O(n) computation overhead. Furthermore, the adopted techniques enable the system to achieve unique characteristics such as accessibility, consistency, and verifiability, as supported by the security analysis provided.

DVIT—A Decentralized Virtual Items Trading Forum with Reputation System

The metaverse provides us with an attractive virtual space in which the value of the virtual property has been increasingly recognized. However, the lack of effective cross-metaverse trading tools and the reputation guarantee makes it difficult to trade items among different metaverses. To this end, a decentralized reputation system for virtual items trading forum named DVIT is devised. To the best of our knowledge, DVIT is the first decentralized cross-metaverse item trading prototype inspired by the online-game trading system. We designed the corresponding transaction function and realized the autonomous governance of the community by introducing the reputation mechanism. An improved election mechanism is proposed to improve efficiency based on Delegated Proof-of-Stake (DPoS). Through token rewards associated with activity levels, users’ motivation can be stimulated. The experiments indicate that our proposed scheme could dynamically measure the trustworthiness degree of the users through the dynamic reputation value and thereby exclude malicious users from the blockchain within 20 epochs.

Generalized Secure and Dynamic Decentralized Reputation System With a Dishonest Majority

Reputation management systems are essential for establishing trust among network users. They are tools for reinforcing cooperation and sanctioning malicious behavior. This importance becomes a requirement in decentralized environments such as mobile ad-hoc networks (MANETs), peer-to-peer systems (P2P), wireless sensor networks (WSNs), or decentralized social networks (DSNs) where there is no trusted third party to monitor and enforce good behavior among users. In this paper, we propose a dynamic decentralized reputation system that fits such network characteristics, namely decentralization, dynamism, and openness, without conceding on security. The novel system is a general-purpose system that uses blockchain to gather and supply global reputation information while remaining fully decentralized. Unlike previous works on decentralized reputation systems where reputation information is inconsistent and limited to users’ direct experience and recommendations from peers (neighbors), our system gathers feedback from all over the network and stores reputation information on a distributed ledger fully accessible to all users. In terms of security, the proposed method achieves privacy utilizing secure multiparty computation, a cryptographic primitive that preserves feedback privacy even with a dishonest majority reaching <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n-2$ </tex-math></inline-formula> malicious parties while requiring only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$O(n)$ </tex-math></inline-formula> messages. The employed techniques enable the system to achieve unique characteristics like consistency, conservation, and verifiability in addition to privacy. The security analysis we provide confirms these properties, and the performed simulation shows the protocol’s effectiveness.

A blockchain-based reputation system for trusted VANET nodes

Vehicular network applications, such as Local Danger Warnings (LDW), have become necessary as they provide services to drivers with warnings and instructions to ensure safe driving. However, before any vehicle reacts to an alert, it is essential to verify its veracity because an incorrect warning misleads other vehicles and causes unnecessary delays and detours in traffic. On the other hand, ignoring an alert or taking too long to verify it can cause accidents. A common way to address this problem is via a reputation system, where the veracity and plausibility of an alert message are assessed based on the reputation of the vehicle that discloses it. This paper describes a decentralized reputation system based on a consortium blockchain and smart contracts called BRS4VANETs. This system analyzes the reliability of data generated by a vehicle, detects malicious behavior, and contributes to decision-making. The complete functional architecture of the system, detailing the algorithms, evaluation metrics, communication protocol, and message formats, is described and implemented. Experiments with network and traffic simulators evaluated the risk of a false message attack, the effectiveness of the system and its overheads. The assessment demonstrates the importance of reputation systems and also shows the feasibility of having a decentralized system to store and disseminate reputation information based on blockchain technologies. Finally, the results also demonstrate that BRS4VANETs can successfully detect suspicious and malicious vehicles.

Incorporating Registration, Reputation, and Incentivization Into the NFT Ecosystem

Non-Fungible Tokens (NFTs) have recently received immense popularity in the digital art industry. An NFT represents ownership of a unique item that is stored on the blockchain and cannot be changed, replaced, and copied. The current NFT ecosystem falls short in trust features and is prone to illegitimate users, threats, and vulnerabilities. In this paper, we propose a blockchain-based solution for the NFT ecosystem that incorporates registration of the participating actors, involves a decentralized reputation system, provides incentives to its users through rewards, and penalizes misconduct. Our system design is built to ensure trust and credibility in the NFT ecosystem. The proposed solution leverages blockchain&#x2019;s intrinsic security features such as transparency, tamper-proof logs, data integrity, accountability, and non-repudiation. We use the decentralized storage of the InterPlanetary File System (IPFS) to store the NFTs&#x2019; metadata, whereas their hash is stored on the chain. We present algorithms along with their implementation, testing, and validation details. We demonstrate how our solution, as well as smart contract code, is secure enough against common security threats and attacks. We make our smart contract code publicly available on the GitHub repository.

REPUTABLE–A Decentralized Reputation System for Blockchain-Based Ecosystems

Reputation systems are an important means to facilitate trustworthy interactions between on-and off-chain services and users. However, contemporary reputation systems are typically dependent on a trusted central authority to preserve privacy of raters or on adding noise into the user feedback. Moreover, the accuracy of reputation values relies on the integrity of user feedback or input; this feedback should not be tampered with or misused for other purposes. This paper presents blockchain-based reputation system named REPUTABLE (A Decentralized Reputation System for blockchain-based Ecosystems), which computes the reputation of service providers and external services within a blockchain ecosystem through decentralized on-chain and off-chain implementation. Specifically, REPUTABLE not only ensures privacy, but also reliability, integrity and accuracy of reputation values, while incurring minimal overhead. It also enables performing certain data or statistical analytics functions on user feedback, whilst preserving security, privacy, accountability and unlinkability of participants and their feedback. We present a proof-of-concept implementation and a demonstration of the REPUTABLE system. Finally, by means of formal and empirical evaluation, we show the effectiveness of our proposed system to preserve the anonymity of user feedback and the high performance of its blockchain-based implementation.

Blockchain-based decentralized reputation system in E-commerce environment

With the rapid development of E-commerce, more and more people are used to shopping online, in which the reputation scores of sellers play an important role in helping consumers purchase satisfactory products. However, in the existing E-commerce environments, the reputation scores of users (including sellers and buyers) are centrally computed and stored on a centralized cloud server, which might make errors or even engage in fraud and forgery. To address this issue, we propose a blockchain-based decentralized reputation system (BC-DRS) in the E-commerce environment, i.e., online shopping. In this system, the product information including product descriptions and comments is stored in the interplanetary file system (IPFS) and the corresponding address is returned, and the returned address and the reputation scores of users are stored on the blockchain. The reputation evaluation is implemented by designing and deploying a smart contract on the blockchain. Different from the traditional centralized reputation systems (CRSs), the proposed BC-DRS can protect the product information and users reputation scores from intentional and unintentional modifications, since it is very hard to change any data stored in the blockchain and IPFS. Also, as the reputation scores of users are computed and updated by all the ratings of their transactions weighted by the practical transaction factors, it is effective to resist the common attacks, i.e., unfair rating and collusion. In addition, this system also contains a monetary incentive mechanism for the evaluation, which is helpful to form a virtuous circle in online shopping. The proposed BC-DRS is simulated on the popular blockchain platform, i.e., Ethereum with Solidity language. The experimental results and analysis demonstrate that the proposed BC-DRS has desirable usability and reliability.

PrivBox: Verifiable decentralized reputation system for online marketplaces

In online marketplaces (e-commerce, cloud marketplaces), potential buyers/consumers do not have direct access to inspect the quality of products and services offered by retailers and service providers of marketplaces. Therefore, consumers have to trust the reputation system of the marketplace for making a meaningful decision whether they should have interaction with the particular service provider or not. Consumer’s feedback plays an important role while evaluating the trustworthiness of the service provider, but it brings challenges to security and the consumer’s privacy. Existing centralized reputation systems collect and process consumer’s feedback at the centralized trusted system but these systems could leak sensitive information of consumers (such as buying history, likes and dislikes). To ensure the privacy of consumers, in this paper, we present PrivBox, a privacy-preserving decentralized reputation system that computes reputation of retailers or service providers by leveraging feedback from users in a secure and private way. The PrivBox system uses primitives of a homomorphic cryptographic system and non-interactive zero-knowledge proof to achieve objectives of privacy-preservation and well-formedness. PrixBox performs its operations in a decentralized setting, and ensures the following characteristics. (1) It guarantees privacy of consumers without relying on any trusted setup or trusted third party system, (2) it ensures that the consumer’s feedback ratings remain within the prescribed range, and (3) it enables consumers and service providers to verify the computed statistics without relying on a trusted third party. To evaluate the performance, we have implemented operations of the PrivBox system. The results demonstrate that the proposed system has a small communication and computation overheads with the essential properties of privacy-preservation and decentralization.

Dynamic, Privacy-Preserving Decentralized Reputation Systems

Reputation systems provide an important basis for judging whether to interact with others in a networked system. Designing such systems is especially interesting in decentralized environments such as mobile ad-hoc networks, as there is no trusted authority to manage reputation feedback information. Such systems also come with significant privacy concerns, further complicating the issue. Researchers have proposed privacy-preserving decentralized reputation systems (PDRS) which ensure individual reputation information is not leaked. Instead, aggregate information is exposed. Unfortunately, in existing PDRS, when a party leaves the network, all of the reputation information they possess about other parties in the network leaves too. This is a significant problem when applying such systems to the kind of dynamic networks we see in mobile computing. In this article, we introduce dynamic, privacy-preserving reputation systems (Dyn-PDRS) to solve the problem. We enumerate the features that a reputation system must support in order to be considered a Dyn-PDRS. Furthermore, we present protocols to enable these features and describe how our protocols are composed to form a Dyn-PDRS. We present simulations of our ideas to understand how a Dyn-PDRS impacts information availability in the network, and report on an implementation of our protocols, including timing experiments.

Multi-Path Routing and Forwarding in Non-Cooperative Wireless Networks

Multi-path routing and forwarding in non-cooperative networks is extremely challenging due to the co-existence of both rational and Byzantine nodes. They both might deviate from the protocol; however, their intentions and behaviors are totally different. Rational nodes aim to maximize their utilities, while Byzantine nodes purposefully deviate from the protocol to disrupt the normal operation of a network. Most work in the literature treat both kinds of misbehavior without distinction and thus lead to ineffective solutions. This paper presents a hybrid design that seamlessly integrates mechanisms for different misbehavior in a unified framework. The GSP auction provides incentives for rational nodes to cooperate and results in truth-telling Nash equilibria. With the possible inclusion of Byzantine nodes in the least cost paths selected by GSP, the FORBID mechanism builds a decentralized reputation system such that malicious behavior is effectively detected. This in turn triggers the GSP auction to update the least cost paths so as to exclude the malicious nodes from being selected for communication. It is proved that the unified protocol is cooperation-optimal. Experiments have been conducted to further investigate the performance of the proposed protocol and the impact of various parameters.

A robust decentralized reputation management system for service selection

Reputation mechanism is a novel approach to automate QoS-aware service selection in service oriented computing. The reputation system collects ratings on QoS that consumers feedback and aggregates them to derive a reputation value, which can in turn assist other consumers in service selection in future. However, current approaches fail to combat the malicious ratings and hence the calculated reputation values can be biased severely or even manipulated. Moreover, the centralized management of rating data restricts its application to large open environment. In this paper, we present a robust decentralized reputation system which can resist various unfair ratings and manipulation behaviours. It can evolve and become more mature against malicious ratings with the system running continuously. At last, we experimentally verify the robustness of the proposed approach through a simulation study.

SimplyRep: A simple and effective reputation system to fight pollution in P2P live streaming

Peer-to-Peer (P2P) streaming has become a popular platform for transmitting live content. However, due to their increasing popularity, P2P live streaming systems may be the target of user opportunistic actions and malicious attacks, which may greatly reduce streaming rate or even stop it completely. In this article, we focus on a specific type of attack called content pollution, in which malicious peers tamper or forge media data, introducing fake content before uploading it to their partners in the overlay network. Specifically, we present a new decentralized reputation system, named SimplyRep, that quickly identifies and penalizes content polluters, while incurring in low overhead in terms of bandwidth consumption. We evaluate our method with both simulation and experiments in PlanetLab, comparing it against two previously proposed approaches, namely, a centralized black list and a distributed reputation system, in various scenarios. Our results indicate that SimplyRep greatly outperforms the two alternatives considered. In particular, both black list and the distributed reputation method perform poorly when polluters act jointly in a collusion attack, reaching a data retransmission overhead (triggered by polluted chunks received) of 70% and 30%, respectively, whereas the overhead experienced by SimplyRep is at most 2%. Our results also show that SimplyRep is able to quickly isolate almost all polluters under a dissimulation attack, being also somewhat robust to a whitewashing attack, although the latter remains a challenge to effective P2P streaming.

Preserving privacy of feedback providers in decentralized reputation systems

Reputation systems make the users of a distributed application accountable for their behavior. The reputation of a user is computed as an aggregate of the feedback provided by other users in the system. Truthful feedback is clearly a prerequisite for computing a reputation score that accurately represents the behavior of a user. However, it has been observed that users often hesitate in providing truthful feedback, mainly due to the fear of retaliation. We present a decentralized privacy preserving reputation protocol that enables users to provide feedback in a private and thus uninhibited manner. The protocol has linear message complexity, which is an improvement over comparable decentralized reputation protocols. Moreover, the protocol allows users to quantify and maximize the probability that their privacy will be preserved.

Gossip-based aggregation of trust in decentralized reputation systems

Decentralized Reputation Systems have recently emerged as a prominent method of establishing trust among self-interested agents in online environments. A key issue is the efficient aggregation of data in the system; several approaches have been proposed, but they are plagued by major shortcomings. We put forward a novel, decentralized data management scheme grounded in gossip-based algorithms. Rumor mongering is known to possess algorithmic advantages, and indeed, our framework inherits many of their salient features: scalability, robustness, globality, and simplicity. We also demonstrate that our scheme motivates agents to maintain a sparkling clean reputation, and is inherently impervious to certain kinds of attacks.

Analysis of a reputation system for Mobile Ad-Hoc Networks with liars

The application of decentralized reputation systems is a promising approach to ensure cooperation and fairness, as well as to address random failures and malicious attacks in Mobile Ad-Hoc Networks. However, they are potentially vulnerable to liars. With our work, we provide a first step to analyzing robustness of a reputation system based on a deviation test. Using a mean-field approach to our stochastic process model, we show that liars have no impact unless their number exceeds a certain threshold (phase transition). We give precise formulae for the critical values and thus provide guidelines for an optimal choice of parameters.