scholarly journals Rational Protocols and Attacks in Blockchain System

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Tao Li ◽  
Yuling Chen ◽  
Yanli Wang ◽  
Yilei Wang ◽  
Minghao Zhao ◽  
...  

Blockchain has been an emerging technology, which comprises lots of fields such as distributed systems and Internet of Things (IoT). As is well known, blockchain is the underlying technology of bitcoin, whose initial motivation is derived from economic incentives. Therefore, lots of components of blockchain (e.g., consensus mechanism) can be constructed toward the view of game theory. In this paper, we highlight the combination of game theory and blockchain, including rational smart contracts, game theoretic attacks, and rational mining strategies. When put differently, the rational parties, who manage to maximize their utilities, involved in blockchain chose their strategies according to the economic incentives. Consequently, we focus on the influence of rational parties with respect to building blocks. More specifically, we investigate the research progress from the aspects of smart contract, rational attacks, and consensus mechanism, respectively. Finally, we present some future directions based on the brief survey with respect to game theory and blockchain.

2021 ◽  
Vol 4 ◽  
Author(s):  
Renita M. Murimi

This paper studies contractual graphs, where the formation of edges between nodes result in dyadic exchanges. Each dyadic exchange is analyzed as a contractual agreement that is implemented upon fulfilment of underlying conditions. As these dyadic exchanges proliferate, the resulting population of these exchanges creates a contractual graph. A contractual framework for graphs is especially useful in applications where AI-enabled software is employed to create or automate smart contracts between nodes. While some smart contracts may be easily created and executed, others may contain a higher level of ambiguity which may prevent their efficient implementation. Ambiguity in contractual elements is especially difficult to implement, since nodes have to efficiently sense the ambiguity and allocate appropriate amounts of computational resources to the ambiguous contractual task. This paper develops a two-node contractual model of graphs, with varying levels of ambiguity in the contracts and examines its consequences for a market where tasks of differing ambiguity are available to be completed by nodes. The central theme of this paper is that as ambiguity increases, it is difficult for nodes to efficiently commit to the contract since there is an uncertainty in the amount of resources that they have to allocate for completion of the tasks specified in the contract. Thus, while linguistic ambiguity or situational ambiguity might not be cognitively burdensome for humans, it might become expensive for nodes involved in the smart contract. The paper also shows that timing matters—the order in which nodes enter the contract is important as they proceed to sense the ambiguity in a task and then allocate appropriate resources. We propose a game-theoretic formulation to scrutinize how nodes that move first to complete a task are differently impacted than those that move second. We discuss the applications of such a contractual framework for graphs and obtain conditions under which two-node contracts can achieve a successful coalition.


2022 ◽  
Vol 22 (2) ◽  
pp. 1-21
Author(s):  
Hongyang Yan ◽  
Nan Jiang ◽  
Kang Li ◽  
Yilei Wang ◽  
Guoyu Yang

At present, clients can outsource lots of complex and abundant computation, e.g., Internet of things (IoT), tasks to clouds by the “pay as you go” model. Outsourcing computation can save costs for clients and fully utilize the existing cloud infrastructures. However, it is hard for clients to trust the clouds even if blockchain is used as the trusted platform. In this article, we utilize the verification method as SETI@home by only two rational clouds, who hope to maximize their utilities. Utilities are defined as the incomes of clouds when they provide computation results to clients. More specifically, one client outsources two jobs to two clouds and each job contains n tasks, which include k identical sentinels. Two clouds can either honestly compute each task or collude on the identical sentinel tasks by agreeing on random values. If the results of identical sentinels are identical, then client regards the jobs as correctly computed without verification. Obviously, rational clouds have incentives to deviate by collusion and provide identical random results for a higher income. We discuss how to prevent collusion by using deposits, e.g., bit-coins. Furthermore, utilities for each cloud can be automatically assigned by a smart contract. We prove that, given proper parameters, two rational clouds will honestly send correct results to the client without collusion.


Author(s):  
Norafni Farlina Rahim ◽  
Mohammed Hariri Bakri ◽  
Siti Norbaya Yahaya

FinTech, or financial technology, is an emerging technology in financial transaction. It is disruptive technology which is changing the banking behavior for stakeholders. The thriving emergence of FinTech not only affects the conventional finance industry but also Islamic finance industry, as Islamic finance sector is also embracing FinTech as part of financial revolution. Thus, the Islamic FinTech emerges as faith-based FinTech. This is because Islamic FinTech claimed to comply with Shariah principle in their mechanism and smart contract. There is limited discussion on smart contract and Islamic FinTech and its Shariah principles. Hence, the Shariah principle in smart contract of Islamic FinTech need to be addressed. This chapter tries to delve into the smart contract concept in Islamic FinTech and Shariah principles in the mechanism. The review found that smart contract is currently in the early stage and so is Islamic FinTech. The scholars agreed that FinTech is a Maslahah (interest) to mankind's benefit. However, the smart contract is still in discussion and review.


2021 ◽  
Vol 11 (15) ◽  
pp. 7013
Author(s):  
Aisha Zahid Junejo ◽  
Manzoor Ahmed Hashmani ◽  
Mehak Maqbool Memon

With the widespread of blockchain technology, preserving the anonymity and confidentiality of transactions have become crucial. An enormous portion of blockchain research is dedicated to the design and development of privacy protocols but not much has been achieved for proper assessment of these solutions. To mitigate the gap, we have first comprehensively classified the existing solutions based on blockchain fundamental building blocks (i.e., smart contracts, cryptography, and hashing). Next, we investigated the evaluation criteria used for validating these techniques. The findings depict that the majority of privacy solutions are validated based on computing resources i.e., memory, time, storage, throughput, etc., only, which is not sufficient. Hence, we have additionally identified and presented various other factors that strengthen or weaken blockchain privacy. Based on those factors, we have formulated an evaluation framework to analyze the efficiency of blockchain privacy solutions. Further, we have introduced a concept of privacy precision that is a quantifiable measure to empirically assess privacy efficiency in blockchains. The calculation of privacy precision will be based on the effectiveness and strength of various privacy protecting attributes of a solution and the associated risks. Finally, we conclude the paper with some open research challenges and future directions. Our study can serve as a benchmark for empirical assessment of blockchain privacy.


Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 244
Author(s):  
Yeşem Kurt Peker ◽  
Xavier Rodriguez ◽  
James Ericsson ◽  
Suk Jin Lee ◽  
Alfredo J. Perez

Blockchain is a developing technology that can be utilized for secure data storage and sharing. In this work, we examine the cost of Blockchain-based data storage for constrained Internet of Things (IoT) devices. We had two phases in the study. In the first phase, we stored data retrieved from a temperature/humidity sensor connected to an Ethereum testnet blockchain using smart contracts in two different ways: first, appending the new data to the existing data, storing all sensor data; and second, overwriting the new data onto the existing data, storing only a recent portion of the data. In the second phase, we stored simulated data from several sensors on the blockchain assuming sensor data is numeric. We proposed a method for encoding the data from the sensors in one variable and compared the costs of storing the data in an array versus storing the encoded data from all sensors in one variable. We also compared the costs of carrying out the encoding within the smart contract versus outside the smart contract. In the first phase, our results indicate that overwriting data points is more cost-efficient than appending them. In the second phase, using the proposed encoding method to store the data from several sensors costs significantly less than storing the data in an array, if the encoding is done outside the smart contract. If the encoding is carried out in the smart contract, the cost is still less than storing the data in an array, however, the difference is not significant. The study shows that even though expensive, for applications where the integrity and transparency of data are crucial, storing IoT sensor data on Ethereum could be a reliable solution.


Author(s):  
Charles Garrocho ◽  
Celio Marcio Soares Ferreira ◽  
Ailton Junior ◽  
Carlos Frederico Cavalcanti ◽  
Ricardo R. Oliveira

Through the Industrial Internet of Things (IIoT), a smart factory has entered the boom period expecting significant investments. In this new environment, Machine-to-Machine (M2M) communication has shown immediate potential in IIoT applications. However, most M2M communication implementations use the centralized model in which it requires a reliable intermediary for transactions between machines. Using smart contracts in M2M communication would allow a decentralized network to be used without the need for a trusted intermediary. In order to provide security, privacy, and decentralization in M2M communication and IIoT processes, a middleware based on a smart contract is proposed. Such a proposal is analyzed at the industrial level and evaluated for impacts against the stringent communication requirements that industrial applications require. Experimental results show that the application of smart contracts offers greater security and privacy than traditional proposals, but time requirements of real-time systems must still be optimized for smart contracts to be applied at the industrial field.


2019 ◽  
Vol 14 ◽  
Author(s):  
Khaleel Ahmad ◽  
Afsar Kamal

Background: Privacy enhancing techniques are developed in order to provide strong protection to cyberspace. These techniques aim to allow users to keep their identities hidden during the communication when they are sending email, making payments online, browsing the Web or posting to newsgroups. MixNet is the most practical solution for concealing identities of message and sender’s identities. Objective: It provides sender and receiver anonymity as well as message security. The main goal of MixNet is to overcome vulnerability and enhance the performance of communication. It can efficiently handle the messages of various length and produce desirable results with privacy. The main objective of this paper is to acquire information and concepts regarding MixNet. We also provide guidelines for future research and references. Methods : The designing of MixNet depends on what cryptosystem method is used. Symmetric and Asymmetric both are used. Other methods could be also used such as PIR, CSP and FDR model, RPC, Token-based approach or others. Result: In this paper we provide an overview of MixNet approaches and presented a survey on MixNet based techniques and different models. We also constructed the comparison tables as per our requirements for better understanding. For this purpose, we found a total of 120 articles related to the MixNet published between 1990 and 2018 from the most relevant scientific resources. However, only 86 papers were analyzed due to comprehensiveness and relevancy to this article. Conclusion: Focused on the security and privacy of communication and how it can be achieved. This survey also reveals research progress and research gap on MixNet.


Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1343
Author(s):  
Faiza Loukil ◽  
Khouloud Boukadi ◽  
Rasheed Hussain ◽  
Mourad Abed

The insurance industry is heavily dependent on several processes executed among multiple entities, such as insurer, insured, and third-party services. The increasingly competitive environment is pushing insurance companies to use advanced technologies to address multiple challenges, namely lack of trust, lack of transparency, and economic instability. To this end, blockchain is used as an emerging technology that enables transparent and secure data storage and transmission. In this paper, we propose CioSy, a collaborative blockchain-based insurance system for monitoring and processing the insurance transactions. To the best of our knowledge, the existing approaches do not consider collaborative insurance to achieve an automated, transparent, and tamper-proof solution. CioSy aims at automating the insurance policy processing, claim handling, and payment using smart contracts. For validation purposes, an experimental prototype is developed on Ethereum blockchain. Our experimental results show that the proposed approach is both feasible and economical in terms of time and cost.


Author(s):  
Olivier Tsemogne ◽  
Yezekael Hayel ◽  
Charles Kamhoua ◽  
Gabriel Deugoue

Author(s):  
Shuangjun Li ◽  
Linglong Chen ◽  
Zhong Ma ◽  
Guisheng Li ◽  
Dieqing Zhang

AbstractThe emission of nitrogen oxides (NOx) increases year by year, causing serious problems to our livelihoods. The photocatalytic oxidation of NOx has attracted more attention recently because of its efficient removal of NOx, especially for low concentrations of NOx. In this review, the mechanism of the photocatalytic oxidation of NOx is described. Then, the recent progress on the development of photocatalysts is reviewed according to the categories of inorganic semiconductors, bismuth-based compounds, nitrogen carbide polymer, and metal organic frameworks (MOFs). In addition, the photoelectrocatalytic oxidation of NOx, a method involving the application of an external voltage on the photocatalytic system to further increase the removal efficiency of NOx, and its progress are summarized. Finally, we outline the remaining challenges and provide our perspectives on the future directions for the photocatalytic oxidation of NOx.


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