Im letzten Jahrzehnt hat der Begriff Blockchain aufgrund des Medienrummels um Bitcoin, der ersten Kryptowährung, immense Popularität erlangt. Bald darauf wurde die Blockchain-Technologie zu einer Inspiration für zusätzliche Anwendungen neben Kryptowährungen. Eine solche Anwendung sind Smart Contracts oder Programme mit dem Ziel, die Vereinbarungen eines Vertrags automatisch und sicher ohne die Unterstützung einer zentralen Stelle auszuführen. Derzeit ist Ethereum die wichtigste Blockchain-Plattform für Smart Contracts. Smart Contracts im Ethereum-Netzwerk können Teil einer dezentralen Anwendung sein oder als eigene Einheit existieren. Sie können durch eine externe Transaktion (User) oder eine interne Transaktion (einen Smart Contract) ausgelöst werden. Angesichts der Bedeutung und Sensibilität der Informationen und / oder Daten, mit denen Smart Contracts täglich umgehen, ist es wichtig, ein besseres Verständnis dafür zu erlangen, wie Smart Contracts tatsächlich funktionieren, welche Funktionen sie ausführen und wie sie im Ethereum-Netzwerk miteinander verbunden sind. In dieser Arbeit wird ein Ansatz für das Clustering von Smart Contracts auf Ethereum hinsichtlich der gemeinsamen Funktionalität vorgeschlagen, das die Graphdatenbank Neo4j und andere Visualisierungsmethoden und / oder –werkzeuge verwendet. Es werden verschiedene Datensätze (Partitionen des kompletten Datensatzes an Smart Contracts auf Ethereum), sowie zwei Clustering- Ansätze verwendet, um einen besseren Einblick in die Funktionsweise von Smart Contracts zu erhalten und deren funktionale Ähnlichkeiten zu verstehen.
Pavitra Haveri, U.B. Rashmi, D. G. Narayan, K. Nagaratna · 5 authors
Bitcoin and Cryptocurrencies are the most popular and the earliest applications of Blockchain. A Blockchain is a public ledger that is distributed and decentralized and it is used to carry out transactions online across the entire network of computer systems. It is a recent technology adopted for data security. The non-modifiable property of the blockchain helps to overcome the problem of document forgery. According to researches, about one million students graduate each year and the document issuing authorities have seemed to be compromised for the security credentials of student data. Due to a lack of effective anti-forge mechanism, forged documents often get unnoticed. The use of physical copies of documents creates a huge overhead as it involves manual verification, paper storage, and manual auditing. Various agencies fail to verify the authenticity of the documents and create loopholes. In this paper, in an attempt to solve the above problem, we design a multi-node private blockchain network using the Ethereum framework and create an off-chain storage i.e. private Interplanetary File System (IPFS) to store the documents. We also evaluate the performance of Ethereum blockchain by analysing the impact of various parameters such as varying difficulty level, load, network size, and consensus algorithms.
Abstract Cryptocurrencies play a major role in the global financial ecosystem. Their presence across different geopolitical corridors, including in repressive regimes, has been one of their striking features. In this work, we leverage this feature for bootstrapping Censorship Resistant communication. We conceptualize the notion of stego-bootstrapping scheme and its security in terms of rareness and security against chosencovertext attacks. We present MoneyMorph , a provably secure stego-bootstrapping scheme using cryptocurrencies. MoneyMorph allows a censored user to interact with a decoder entity outside the censored region, through blockchain transactions as rendezvous, to obtain bootstrapping information such as a censorshipresistant proxy and its public key. Unlike the usual bootstrapping approaches (e.g., emailing) with heuristic security, if any, MoneyMorph employs public-key steganography over blockchain transactions to ensure provable cryptographic security. We design rendezvous over Bitcoin, Zcash, Monero, and Ethereum, and analyze their effectiveness in terms of available bandwidth and transaction cost. With its highly cryptographic structure, we show that Zcash provides 1148 byte bandwidth per transaction costing less than 0.01 USD as fee.
Berrak Perk, Can Bayraktaroglu, Engin Deniz Dogu, Faizan Safdar Ali · 5 authors
As a decentralized immutable ledger where several trustless peers can reach consensus with each other without the need of any trusted third party, blockchain technology fits perfectly with the peer-to-peer (P2P) energy trading paradigm. In this paper, we propose, design and analyze a marketplace for energy trading based on smart contracts on the blockchain. The proposed system named Joulin serves as a competitive and efficient marketplace where peers can both produce, buy and sell energy depending on their needs. As a proof-of-concept, we developed the prototype of the Joulin system using Ethereum blockchain. Our results, in terms of usability, flexibility and resiliency, demonstrate the potential to achieve an easily extendable and reliable system with low transaction costs. Low Ethereum gas costs and quick response times demonstrate usability. Our smart contracts have also been tested with security tools to ensure that they are not vulnerable to outside manipulations.
Unmanned aerial vehicle (UAV) is used in various smart applications, such as defense, civilian, and healthcare services. As data in these applications flow through an open channel, i.e., the Internet, so security and privacy always a challenging issue. Though many solutions exist for this problem in literature, but these solutions are not adequate to handle security, privacy, latency, and efficient real-time delivery of healthcare services remotely over the wireless communication channel. Moreover, the existing UAV systems have security, reliability, latency, and storage cost issues, which restricts their applicability shortly. Motivated from these facts, this paper proposes VAHAK, an Ethereum Blockchain (BC) based secure outdoor healthcare medical supplies using UAVs. VAHAK provides reliable communication between the UAVs and the entities in a decentralized manner, which ensures the early delivery of required medical supplies to the critical patients. In VAHAK, security, privacy, and reliability issues have been resolved using Ethereum smart contract (ESC), while storage cost issues are handled with IPFS protocol. The security vulnerabilities of the VAHAK are tested on MyThril open-source tool. VAHAK is efficient in terms of data storage cost as it uses the InterPlanetary File System (IPFS) for healthcare record storage and 5G-enabled Tactile Internet (TI) for communication, respectively. Finally, VAHAK performance evaluation demonstrates its effectiveness as compared to the traditional systems where it outperforms the existing schemes with respect to various performance evaluation metrics, such as scalability, latency, and network bandwidth.
Sajjad Rezaei, Ehsan Khamespanah, Marjan Sirjani, Ali Sedaghatbaf · 5 authors
Blockchain is a shared, distributed ledger on which transactions are digitally recorded and linked together. Smart Contracts are programs running on Blockchain and are used to perform transactions in a distributed environment without need for any trusted third party. Since smart contracts are used to transfer assets between contractual parties, their safety and security are crucial and badly written and insecure contracts may result in catastrophe. Actor-based programming is known to solve several problems in building distributed software systems. Moreover, formal verification is a solid technique for developing dependable systems. In this paper, we show how the actor model can be used for modeling, analysis and synthesis of smart contracts. We propose Smart Rebeca as an extension of the actor-based language Rebeca, and use the model checking toolset Afra for verification of smart contracts. We implement a synthesizer to synthesize Solidity programs that run on the Ethereum platform from Smart Rebeca models. We examine the challenges and opportunities of our approach in modeling, formal verification, and synthesis of smart contracts using actors.
Conventional certificate verification, whether paper-based or backed by a centralized digital registry, remains exposed to forgery, single points of failure, and slow manual cross-checking between issuers, holders, and verifiers. This paper presents a decentralized, blockchain-based framework for issuing, storing, and verifying academic and professional certificates that addresses these weaknesses without placing the full document on-chain. Each certificate is reduced to a SHA-256 hash, signed with the issuing institution's RSA private key, and recorded through an Ethereum smart contract, while the original file is retained off-chain on IPFS and referenced by its Content Identifier. Only institutions that pass a unanimous, vote-based onboarding process administered by a validator consortium are permitted to issue certificates, which constrains the system to a trusted-issuer model while preserving decentralization across the validator set. A hash-mapped Bloom Filter sits in front of the blockchain query path and performs a fast probabilistic existence check, allowing forged or non-existent certificates to be rejected before an on-chain lookup is triggered. A prototype was implemented with Solidity smart contracts on the Ethereum Sepolia testnet, a Node.js/Web3.js application layer, and a React.js frontend with MetaMask-based authentication. Evaluation on the testnet shows that the Bloom Filter pre-check lowers the average lookup time for invalid certificates by roughly 87%, keeps verification of valid certificates under two seconds end-to-end, holds the false-positive rate below 0.5% for up to 50,000 stored certificate hashes, and reduces the gas cost of issuing a certificate to approximately 4.57 USD. These results indicate that combining consortium governance, cryptographic hashing, and probabilistic filtering yields a certificate validation pipeline that is simultaneously tamper-resistant, low-cost, and fast enough for real-time institutional use.
Smart contracts vulnerability auditing is vitally critical to ensure transaction execution in normal on blockchain. The current data-driven approaches normally tokenize smart contracts into a series of sequences according to only one tokenization standard for vulnerability detection purpose, resulting some of the semantic contexts could not be reflected within restricted sequence length. To address this limitation, we generate sequences from smart contracts in three tokenization standards for which we utilize n-gram language model to capture semantic contexts respectively, and finally exploiting our effective combination strategy of Intersection or Union to integrate the audited results from multiple semantic contexts. In order to evaluate the proposed approach, we applied it on over 7200 Ethereum smart contract samples. Experimental result shows our proposed method is capable of detecting vulnerabilities and competitive with the baseline in test sets, with improved precision of over 44% when Intersection is applied in their results, as well as improved Recall measure up by over 300% and F-measure up by 220% when Union is applied. Our proposed method for smart contract vulnerability detection, an important tool for developing quality decentralized software applications, is able to analyze multiple semantic contexts and successfully detects more true vulnerabilities with high precision, outperforming that of the baseline approaches.
U. Palani, Sure Sai Mahesh, D. Vasanthi, D. Sathish Kumar
Thirty-five % of the US population is affected by data breach occurred in the healthcare industry. It is a total of 114 million people affected in 2015. On average of 4 data breaches happens per week. Health care industry is losing 300 billion dollars each year in poor data integration. we can overcome this problem by bringing a decentralized system in the hospital organization. This prototype helps us to stop and prevent data breaching in the health care industry and to remove fake patient IDs in the hospital data base.
Tam Bang, Hoang H. Nguyen, Dung Nguyen, Toan Trieu · 5 authors
Ethereum smart contracts based on blockchain technology are powerful and promising applications that provide a global platform for exchanging cryptocurrencies and public services. This technology are garnering a huge impact and is widely adopted in the current times as it can transform the way we transfer and exchange value by passing the need for a middleman and reducing cost. These smart contracts also represent a basis for true ownership of digital assets and a wide range of decentralized applications. Besides this, since Ethereum and its smart contracts are a publicly accessible, unchangeable and distributed platform, they are extremely vulnerable to various forms of attack, with their security becoming a top priority. However, current security-verifying programs tend to provide many technical details which are pretty hard for normal people to understand briefly. To tackle this problem, we designed a process aiming to mitigate these limitations, with our key insight being a combination of semantic structure analysis and symbolic execution on control-flow graphs (CFG for short). This article proposes a new approach for auditing Ethereum smart contracts, applying this technique would benefit both average users without any technical knowledge and security experts as well.
S.A. Pranesh, Vignesh Kannan V., N. Viswanathan, M. Vijayalakshmi
Blockchain is becoming more popular because of its decentralized, secured, and transparent nature. Supply chain and its management is indispensable to improve customer services, reduce operating costs and improve financial position of a firm. Integration of blockchain and supply chain is substantial, but it alone is not enough for the sustainability of supply chain systems. The proposed mechanism speaks about the method of rewarding the supply chain parties with incentives so as to improve the security and make the integration of supply chain with blockchain sustainable. The proposed incentive mechanism employs the co-operative approach of game theory where all the supply chain parties show a cooperative behavior of following the blockchain-based supply chain protocols and also this mechanism makes a fair attempt in rewarding the supply chain parties with incentives.
The global daily data generation is estimated to be more than 2.5 quintillion bytes, and more than 90 percent of the total data produced is generated in the last two years. Most of this data is being generated and controlled by very few centralized agencies in the Web 2.0 internet architecture. This causes issues, including data manipulation, lack of privacy, and data leaks historically and is not just limited to the fields mentioned. This paper proposes a Web 3.0 based architecture which eliminates the centralized agencies and to promote a fully decentralized, secure, and transparent internet. It leverages IPFS, a peer to peer distributed hypermedia transfer protocol. Ethereum and smart contracts create a secure decentralized mechanism for initiating data-based payments. Furthermore, the proposed architecture uses zero-knowledge proofs and proxy re-encryption mechanisms to enhance the privacy of the nodes in the network.
Traditional stock exchange systems are centralized and have high transaction fees, third party brokerage and less secure environment vulnerable to attacks. Blockchain decentralizes the exchange and creates a fair trading environment for every individual. This paper aims to implement a decentralized stock exchange based on blockchain. The proposed system aims to bring down the transaction costs and reduce the time taken to settle orders and eliminate the need of third parties for executing trades. Three different contracts one for buyer, seller and exchange are used to separate stock exchange functionality and optimize transaction costs. The system is implemented using Ethereum. The system is evaluated for scalability of number of transactions and scalability of number of nodes using sampled trading data from NASDAQ. Transaction fees for the miner at 16.5 Gwei is 99.98% lesser than the brokerage fees of traditional traders for the same transactions. Experimental results of the proposed method show that it is possible to eliminate third party brokerages, reduce transaction fees to almost 0 and create a peer-to-peer trading environment that does not require a central exchange.
Ever since peer to peer transaction paradigm was implemented, there has been a certain belief that it can be used effectively in the commercial sector. The freelance economy has witnessed massive growth over the years, while India is the largest freelancing market with over 10 million freelancers. Freelancer is the person who works under different employers to earn money, with no assurance of long-time commitment to a particular employer. There are multiple centralised freelancing websites present but the problem with the centralised system is that it can be manipulated. In these platforms, freelancers and employers are dependent on the third-party for payment contracts. Hence, we are proposing a decentralised system based on public Blockchain Ethereum to resolve the issues generated by the third party. The proposed system will have peer to peer transaction using cryptocurrency and peer to peer reviews on the distributed ledger of Ethereum.
A smart grid (SG) system offers many services to the end-users, such as load management, load forecasting, and energy trading (ET). As data among different devices in SG environment flows through an open channel, i.e., Internet, so, security and privacy always remains a challenging issue. Though many solutions exist for this problem in literature but these solutions are not adequate to handle security, privacy, latency, real-time settlement of ET. Moreover, most of the solutions reported in the literature are based upon the centralized architecture having single point of failure. Motivated from these facts, this paper proposes a scheme ET-DeaL, which is a Smart Contract-based Secure Energy Trading scheme for SG system for peer-to-peer (P2P) ET. ET-DeaL uses Ethereum smart contract (ESC) and Inter Planetary File System (IPFS) for the P2P ET management. Moreover, it manages the energy load of residential houses, industries, and electric vehicles (EVs). In ET-DeaL, security and privacy issues have been resolved using ESC, while storage cost issues are handled with IPFS protocol. We implemented a real time ESC and deploy it in Truffle suite. The security bugs of the ET-DeaL are tested on MyThril open-source tool. Finally, ET-DeaL performance evaluation demonstrates its effectiveness as compared to the traditional systems where it outperforms the existing schemes with respect to various performance evaluation metrics.
Chengjun Cai, Lei Xu, Anxin Zhou, Ruochen Wang · 6 authors
The rapid growth of Ethereum blockchain has brought extremely heavy overhead for coin owners or developers to bootstrap and access transactions on Ethereum. To address this, light client is enabled, which only stores a small fraction of blockchain data and relies on bootstrapped full nodes for transaction retrievals. However, because the retrieval requests are outsourced, it raises several severe concerns about the integrity of returned results and the leakage of sensitive blockchain access histories, largely hindering the wider adoption of this important lightweight design. In addition to security issues, the continuously increasing blockchain storage also urges for more effective query functionalities for the Ethereum blockchain, so as to enable more flexible and precise transaction retrievals.In this paper, we propose EncELC, a new Ethereum light client design that enforces full-fledged protections for clients and enables rich queries over the Ethereum blockchain. EncELC leverages trusted hardware (e.g., Intel SGX) as a starting point for building efficient yet secure processing, and further crafts several crucial performance and security refinement designs to boost query efficiency and conceal leakages inside and outside SGX enclave. We implement a prototype of EncELC and test its performance in several real settings, and the results have confirmed the practicality of EncELC.
IoT has proven valuable in many industries such as Supply Chain, Shipping and Transportation providing updates on the status of shipments in real time. This has resulted in a large amount of data created by IoT devices that require real time processing. Blockchain has also emerged as a trusted common data storage among multiple participants in IoT systems. However, it is essential to verify the authenticity of data before they go in to the blockchain. Some IoT data must be also encrypted in a secure manner. In this paper, we propose a method to collect sensor data from IoT devices and use blockchain to store and retrieve the collected data in a secure and decentralized fashion. A testbed private blockchain system with Ethereum and Raspberry Pi has been developed to test the feasibility and performance of blockchain-based secure IoT system. We employ private PKI for key management and TPM for storing keys, signing, verifying and encrypting data in a trusted way. We describe the structure of the testbed, decentralized storage system based on Ethereum Swarm and IPFS, TPM configuration processes, smart contract codes, and detailed operation sequences. Performance has been measured with 5000 test transactions in 8 different configurations. The result shows that Ethereum blockchain with Swarm can offer about 9 transactions per second. Encryption and decryption is shown to reduce the performance slightly to about 8 transactions per second. The proposed system can provide a secure IoT Blockchain platform for small industrial applications at low cost.
Jiachi Chen, Xin Xia, David Lo, John Grundy · 5 authors
Software development is a very broad activity that captures the entire life cycle of a software, which includes designing, programming, maintenance and so on. In this study, we focus on the maintenance-related concerns of the post-deployment of smart contracts. Smart contracts are self-executed programs that run on a blockchain. They cannot be modified once deployed and hence they bring unique maintenance challenges compared to conventional software. According to the definition of ISO/IEC 14764, there are four kinds of software maintenance, i.e., corrective, adaptive, perfective, and preventive maintenance. This study aims to answer (i) What kinds of issues will smart contract developers encounter for corrective, adaptive, perfective, and preventive maintenance after they are deployed to the Ethereum? (ii) What are the current maintenance-related methods used for smart contracts? To obtain the answers to these research questions, we first conducted a systematic literature review to analyze 131 smart contract related research papers published from 2014 to 2020. Since the Ethereum ecosystem is fast-growing, some results from previous publications might be out-of-date and there may be a gap between academia and industry. To address this, we performed an online survey of smart contract developers on Github to validate our findings and received 165 useful responses. Based on the survey feedback and literature review, we present the first empirical study on smart contract maintenance-related concerns. Our study can help smart contract developers better maintain their smart contract-based projects, and we highlight some key future research directions to improve the Ethereum ecosystem.
In recent years, blockchain technology has created a new cryptocurrency world and has attracted a lot of attention. It also is rampant with various scams. For example, phishing scams have grabbed a lot of money and has become an important threat to users' financial security in the blockchain ecosystem. To help deal with this issue, this paper proposes a systematic approach to detect phishing accounts based on blockchain transactions and take Ethereum as an example to verify its effectiveness. Specifically, we propose a graph-based cascade feature extraction method based on transaction records and a lightGBM-based Dual-sampling Ensemble algorithm to build the identification model. Extensive experiments show that the proposed algorithm can effectively identify phishing scams.
The scope of the existing distributed ledger technologies is divergent in terms of technological features, as well as in their acceptance among the user and developer communities. In this paper, we propose a set of diverse criteria for the evaluation of a distributed ledger ecosystem, which does not focus only on the technological aspects of viable solutions. They also consider decentralized application development perspective and sustainability of its use. We provide a brief overview of some of the alternative distributed ledger ecosystems for the development and deployment of business and IoT decentralized applications. The set of investigated technologies and networks includes Ethereum, Hyperledger, Hedera Hashgraph, EOS, Corda, IOTA, and Multichain.
Currently, technologies are developing very quickly and the need for information security is constantly increasing. In this connection, Blockchain technology is becoming in demand, which allows us to keep information safety and integrity. In addition, the technology enables the creation of a decentralized environment where transactions and data are take place without any third party organization. We proposed a decentralized web resource based on the Ethereum platform for managing student credits. The decentralized application (Dapp), will process, manage and control tokens, which represent credits that students gain for completed certain courses. The credit system is a first step towards a more transparent and technologically advanced form which could be used by universities and students to manage credits. The novelty of this scientific research is the creation of a web-based information resource based on Blockchain technology. Thanks to this resource, it becomes possible to track students' grades and receive reliable information about higher education. This completely eliminates the possibility of making changes to existing records.
The current pandemic situation has made us realize how fake news can have detrimental impacts on society. Although we can't ignore the benefits of social media, we surely can't overlook the misuse of these mediums to spread rumors and fake articles. These posts/ articles/ messages can be commonly called "Fake News" and they not only create misinformation but also create panic among the public. Blockchain is a disruptive technology that is being used to make innovative solutions in the sectors of food, fashion, supply chain, and banking. The decentralized and transparent nature of blockchain can not only be used in the above sectors but it can also be used to tackle the problem of fake news. Several solutions have been proposed to combat the problem using blockchain. This paper will propose one such solution to combat the fake news problem that can be used by all the news agencies. The system is called the "News Tracking and Tracing System " and is built using Ethereum.