Heuristics Analyses of Smart Contracts Bytecodes and Their Classifications

Smart contracts on a blockchain network can be implemented to control digital value. A key question that arises is the extent to which smart contracts can, or should, operate as “smart legal contracts”. Simply put, can smart contracts meet requirements of validity at law and practical efficacy. In order to achieve the goal of value maximization, the efforts of policy-makers, standards organisations and regulators should be informed by first principles. Standards, and other regulatory activities, must be driven by consideration of the techno-legal functions of contracting. Blockchain-based smart contracts offer the potential to reduce transaction costs through new methods of stateful computation. When applied to commercial transactions, smart contracts can represent enforcement of an executed state. This paper argues that distributed ledger and smart contracts standards should seek to provide sufficient flexibility to facilitate contracting parties to coordinate in an optimal manner.

Blockchain technology and its applications are gaining popularity day by day. It is a ground-breaking technology that allows users to communicate without the need of a trusted middleman. A smart contract (self-executable code) is deployed on the blockchain and auto executes due to a triggering condition. In a no-trust contracting environment, smart contracts can establish trust among parties. Terms and conditions embedded in smart contracts will be imposed immediately when specified criteria have been fulfilled. Due to this, the malicious assailants have a special interest in smart contracts. Blockchains are immutable means if some transaction is deployed or recorded on the blockchain, it becomes unalterable. Thus, smart contracts must be analyzed to ensure zero security vulnerabilities or flaws before deploying the same on the blockchain because a single vulnerability can lead to the loss of millions. For analyzing the security vulnerabilities of smart contracts, various analysis tools have been developed to create safe and secure smart contracts. This paper presents a systematic review on Ethereum smart contracts analysis tools. Initially, these tools are categorized into static and dynamic analysis tools. Thereafter, different sources code analysis techniques are studied such as taint analysis, symbolic execution, and fuzzing techniques. In total, 86 security analysis tools developed for Ethereum blockchain smart contract are analyzed regardless of tool type and analysis approach. Finally, the paper highlights some challenges and future recommendations in the field of Ethereum smart contracts.

Unmanned aerial vehicles (UAV), an emerging architecture that embodies flying ad-hoc networks, face critical privacy and security challenges, mainly when engaged in data-sensitive missions. Therefore, message authentication is a crucial security feature for drone communication. This paper presents a Blockchain-based Efficient, and Trusted Authentication scheme for UAV communication BETA-UAV, which exploits the inherent properties of blockchain technology concerning memorability and immutable to record communication sessions via transaction using a smart contract. The smart contract in BETA-UAV allows participants to publish and call transactions from the blockchain network. Furthermore, the transaction addresses are proof of freshness and trustworthiness for subsequent transmissions. Furthermore, we investigate the ability to resist active attacks, e.g., impersonation, replaying, and modification. In addition, we evaluate the gas costs associated with the smart contract's functions by implementing BETA-UAV on the Ethereum public blockchain. Comparing computation and communication over-heads shows that the proposed approach can save significant costs over traditional techniques.

Smart contracts are decentralized applications running on the blockchain to meet various practical scenario demands. The increasing number of security events regarding smart contracts have led to huge pecuniary losses and destroyed the ecological stability of contract layer on the blockchain. Faced with the increasing quantity of contracts, it is an emerging issue to effectively and efficiently detect vulnerabilities in smart contracts. Existing methods of detecting vulnerabilities in smart contracts like Oyente mainly employ symbolic execution. This method is very time-consuming, as the symbolic execution requires the exploration of all executable paths in a contract. In this work, we propose an efficient model for the detection of vulnerabilities in Ethereum smart contracts with machine learning techniques. The model is able to effectively and fast detect vulnerabilities based on the patterns learned from training samples. Our model is evaluated on 49502 real-world smart contracts and the results verify its effectiveness and efficiency.

With the growing utility of blockchain technology, the desire for reciprocal interactions among different blockchains is growing. However, most operational blockchain networks currently operate in a standalone setting. This fragmentation in the form of isolated blockchains creates interoperability difficulties, inhibiting the adoption of blockchains in various ecosystems. Interoperability is a key factor in the healthcare domain for sharing EHRs of patients registered in independent blockchain networks. Each blockchain network could have its own rules and regulations, obstructing the exchange of EHRs for improving diagnosis and treatments. Examples include patients being treated by healthcare providers in different countries or regions, or within one country but with a different set of rules per state or emirate. By contrast, a federation of blockchain networks can provide better communication and service to stakeholders in healthcare. Thus, solutions for facilitating inter-blockchain communication in such a blockchain federation are needed. However, this possibility has not been fully explored, and further investigations are still being conducted. Hence, the present study proposes a transaction-based smart contract triggering system for inter-blockchain communication, enabling EHR sharing among independent blockchains. We use local and global smart contracts that will be executed once a transaction is created in the blockchain. Local smart contracts are used for EHR sharing within the blockchain, whereas global smart contracts are used for EHR sharing among independent blockchains. The experimental setup is conducted using the Hyperledger Fabric blockchain platform. Inter-blockchain communication between two independent fabric networks is conducted through a global smart contract using Hyperledger Cactus for EHR sharing in a health federation setup. To the best of our knowledge, our study is the first to implement an inter-blockchain communication model in the healthcare domain.

In the last few years, the technological future becoming apparent by the introduction of smart contracts into mainstream technology, specifically in the development of Web3 and the metaverse. Smart contracts will play a vital role in the decentralization and autonomy of the day-to-day tasks that must be completed. Several literature reviews, considered secondary sources, highlight the current state of testing methods for smart contracts made for Blockchain applications. In this paper, we present the results from a systematic mapping study to give structure to the information found from primary sources. Systematic mapping is a well-known method to identify and categorize research papers in a field with an increasing amount of literature. For this systematic mapping, we searched for studies between 2017 and present-day (March 2022) and were able to find 303 results, from which 47 were selected, by specific inclusion and exclusion criteria, to be relevant to this study. A concept map was created from the information gathered from primary sources to the attributes such as research type, contribution type, blockchain network, smart contract language, development process, testing methods, and testing environment. We also categorized the trends and demographics found in the selected papers based on publication year, author’s country, and more. The results of this systematic mapping showed that this field is very new and quickly increasing with new research. The researchers that are interested in this field could use the results found to create opportunities for their future work.

BackgroundAn estimated US $2.6 billion loss is attributed to health care fraud and abuse. With traditional health care claims verification and reimbursement, the health care provider submits a claim after rendering services to a patient, which is then verified and reimbursed by the payer. However, this process leaves out a critical stakeholder: the patient for whom the services are actually rendered. This lack of patient participation introduces a risk of fraud and abuse. Blockchain technology enables secure data management with transparency, which could mitigate this risk of health care fraud and abuse.ObjectiveThe aim of this study is to develop a framework using blockchain to record claims data and transactions in an immutable format and to enable the patient to act as a validating node to help detect and prevent health care fraud and abuse.MethodsWe developed a health care fraud and abuse blockchain technical framework and prototype using key blockchain tools and application layers including consensus algorithms, smart contracts, tokens, and governance based on digital identity on the Ethereum platform (Ethereum Foundation).ResultsOur technical framework maps to the claims adjudication process and focuses on Medicare claims, with the US Centers for Medicare and Medicaid Services (CMS) as the central authority. A prototype of the framework system was developed using the blockchain platform Ethereum (Ethereum Foundation), with its design features, workflow, smart contract functions, system architecture, and software implementation outlined. The software stack used to build the system consisted of a front-end user interface framework, a back-end processing server, and a blockchain network. React was used for the user interface framework, and NodeJS and an Express server were used for the back-end processing server; Solidity was the smart contract language used to interact with a local Ethereum blockchain network.ConclusionsThe proposed framework and the initial prototype have the potential to improve the health care claims process by using blockchain technology for secure data storage and consensus mechanisms, which make the claims adjudication process more patient-centric for the purposes of identifying and preventing health care fraud and abuse. Future work will focus on the use of synthetic or historic CMS claims data to assess the real-world viability of the framework.

Solidity smart contract allow developers to formalize financial agreements between users. Due to their monetary nature, smart contracts have been the target of many high-profile attacks. Brute-force verification of smart contracts that maintain data for up to \(2^{160}\) users is intractable. In this paper, we present SmartACE, an automated framework for smart contract verification. To ameliorate the state explosion induced by large numbers of users, SmartACE implements local bundle abstractions that reduce verification from arbitrarily many users to a few representative users. To uncover deep bugs spanning multiple transactions, SmartACE employs a variety of techniques such as model checking, fuzzing, and symbolic execution. To illustrate the effectiveness of SmartACE, we verify several contracts from the popular OpenZeppelin library: an access-control policy and an escrow service. For each contract, we provide specifications in the Scribble language and apply fault injection to validate each specification. We report on our experience integrating Scribble with SmartACE, and describe the performance of SmartACE on each specification.

Blockchains are distributed ledgers that enable the disintermediation of collaborative processes and, at the same time, foster trust among partners. Modern blockchains support smart contracts, i.e., software deployed on the blockchain, and guarantee their repeatable, deterministic execution. Alas, blockchains and smart contracts lack standardization. Therefore, smart contracts come with heterogeneous properties, APIs and data formats. This hinders the integration of smart contracts running in different blockchains, e.g., into enterprise business processes. This paper introduces the Smart Contract Invocation Protocol (SCIP), which unifies interacting with smart contracts of different blockchains. The protocol supports invoking smart contract functions, monitoring function executions, emitted events, and transaction finality, as well as querying a blockchain. The protocol is accompanied by a prototypical implementation of a SCIP endpoint in the form of a gateway.

Blockchain technology, smart contract and microgrid systems have facilitated innovations and breakthroughs in the electricity industry. The once bundled electricity market dominated by a few key players is now gradually becoming unbundled to a more consumer-centric market due to these new technologies. To facilitate the use of community microgrids, this study develops a new trend in peer-to-peer energy trading. In this work, a model for a smart microgrid system, a decentralized energy trading platform based on blockchain, and smart contract technologies is proposed, considering an islanded community microgrid network of energy prosumers. Smart meters were used to ensure the bi-directional flow of data and power, thereby giving prosumers control over their power usage. Storage and validation of participants’ data are stored on the blockchain network, which has a strong feature of decentralization, transparency, security and data immutability. The smart contract automatically executes power delivery and transfer of tokens from the buyer’s wallet to the seller’s energy wallet based on the transaction logic and protocol. A web-user interface was designed to enable the ease of transactions by market participants and the web-user interface was designed on React.Javascript while the smart contract codes were done on the solidity programming language. Algorithms were also developed for the market trade operations in real time and sets of mathematical equations were formulated for energy pricing based on the supply and demand philosophies to curtail over-pricing and underpricing of energy.

Fuzzing and symbolic execution are two complementary techniques for discovering software vulnerabilities. Fuzzing is fast and scalable, but can be ineffective when it fails to randomly select the right inputs. Symbolic execution is thorough but slow and often does not scale to deep program paths with complex path conditions. In this work, we propose to learn an effective and fast fuzzer from symbolic execution, by phrasing the learning task in the framework of imitation learning. During learning, a symbolic execution expert generates a large number of quality inputs improving coverage on thousands of programs. Then, a fuzzing policy, represented with a suitable architecture of neural networks, is trained on the generated dataset. The learned policy can then be used to fuzz new programs. We instantiate our approach to the problem of fuzzing smart contracts, a domain where contracts often implement similar functionality (facilitating learning) and security is of utmost importance. We present an end-to-end system, ILF (for Imitation Learning based Fuzzer), and an extensive evaluation over >18K contracts. Our results show that ILF is effective: (i) it is fast, generating 148 transactions per second, (ii) it outperforms existing fuzzers (e.g., achieving 33% more coverage), and (iii) it detects more vulnerabilities than existing fuzzing and symbolic execution tools for Ethereum.

The construction industry is among the few industries that contribute to the growth and development of the economy; its size gives a representative potential in contributing to economic development. However, the nature of the construction industry in Egypt is plagued by disputes, which often arise from contractual issues, communication breakdowns, and project management challenges during various stages of the project. Furthermore, construction contracts are always viewed as complex and dense paperwork that makes it difficult to extract necessary information, inhibiting smooth operation. This can be solved by implementing smart contracts. A smart contract can include blockchain technology that executes agreed-upon terms automatically and autonomously. This data-driven mechanism automatically issues payments at the end of each clause, reducing the potential for disputes. The aim of this research is to Investigate the potential of smart contracts in reducing disputes in the construction projects. This study will be performed by adopting a qualitative approach through collecting and analysing data from various literature sources, as books, journals, and existing research, to construct a comprehensive understanding from a holistic point of view focusing on relevant keywords as smart contracts and disputes during various stages in construction projects to identify the relationship between them and present it in a relationship matrix. Second, analysis of case studies to investigate the effectiveness of smart contracts and validate the identified relationship and view its potential in construction projects.

Abstract: Blockchain has become the most mentioned or a trending topic on the internet. Today, it is used for many purposes such as smart contracts, keeping records of financial data for banks, data management for government agencies or servicesbased companies, etc. Blockchains are phlebotomizing money. Now a day there is a plethora of different networks or tokens available. Each and every token and network has its own pros and cons. You can use this cryptocurrency to purchase goods or services on the platform or transfer it to various exchanges. But the point is how this token or cryptocurrency generates revenue from providing different services. How are individual networks able to be upheld value in the blockchain market? This research aims to know what are the different ways through which a blockchain company makes money and what things are important to run a profitable blockchain company and also researches what kind of vulnerability and problems occur in the blockchain. Blockchain networks are not immune to cyberattacks and fraud. Through this, we hope to increase the transparency of the Blockchain Business model to enhance the public's trust in blockchain networks and help to make a decision on which blockchain networks are profitable and good for future investments.

With the emergence of smart home, smart city and smart transportation, attackers using Internet of Things (IoTs) devices to launch Distributed Denial of Service (DDoS) attacks on blockchain are also on the rise, making blockchain network become a major disaster area for DDoS attacks. To solve this problem, the paper proposes a DDoS attack defense method based on blockchain for IoTs devices. This method firstly extracts the feature of network traffic of edge nodes, further analyzes the extracted data feature, detects the abnormal behavior of terminal devices, and finally realizes DDoS attack defense by deploying smart contracts in the blockchain network for attack node information and access control strategy. The method can detect abnormal behavior on IoTs device, which is helpful to identify the attack as soon as possible. The synchronization of DDoS attack node information and defense strategy is realized by smart contract, which avoids network congestion of central node and gains time advantage for attack defense.

Blockchain is a type of decentralized database where all data are kept in one large chain of interconnected blocks of data stored on a large number of servers around the world. Besides decentralization, an additional advantage of this technology is the absence of intermediaries in communication between participants in the process. With the advent of the Ethereum network which is based on blockchain technology, in addition to performing financial transactions, now it is possible to create programs that could be executed on this network. However, execution of these programs, known as Smart Contract, costs money that is billed on this network in the form of gas which is directly proportional to the complexity of the computer operations performed within these contracts. Optimizing the structure and content of smart contracts directly implies reducing the cost/gas for their execution. In this paper we propose the structure of smart contracts in the context of gas optimization for their execution.