Deploy Smart Contracts Research Articles

Automating Comment Generation for Smart Contract from Bytecode

Recently, smart contracts have played a vital role in automatic financial and business transactions. To help end users without programming background to better understand the logic of smart contracts, previous studies have proposed models for automatically translating smart contract source code into their corresponding code summaries. However, in practice, only 13% of smart contracts deployed on the Ethereum blockchain are associated with source code. The practical usage of these existing tools is significantly restricted. Considering that bytecode is always necessary when deploying smart contracts, in this paper, we first introduce the task of automatically generating smart contract code summaries from bytecode. We propose a novel approach, named S mart BT ( Smart contract B ytecode T ranslator) for automatically translating smart contract bytecode into fine-grained natural language description directly. Two key challenges are posed for this task: structural code logic hidden in bytecode and the huge semantic gap between bytecode and natural language descriptions. To address the first challenge, we transform bytecode into CFG (Control-Flow Graph) to learn code structural and logic details. Regarding the second challenge, we introduce an information retrieval component to fetch similar comments for filling the semantic gap. Then the structural input and semantic input are used to build an attentional sequence-to-sequence neural network model. The copy mechanism is employed to copy rare words directly from similar comments and the coverage mechanism is employed to eliminate repetitive outputs. The automatic evaluation results show that SmartBT outperforms a set of baselines by a large margin, and the human evaluation results show the effectiveness and potential of SmartBT in producing meaningful and accurate comments for smart contract code from bytecode directly.

A Prototype of Decentralized Applications (DApps) Population Management System Based on Blockchain and Smart Contract

The Indonesian population reached 270,20 million in 2020. Each resident is equipped with various secret identities. The COVID-19 pandemic has made all activities use technology as a basis, causing residents' identities to be stored digitally. Some applications that keep these identities experience data leaks. However, with the advent of Web3 and its emphasis on decentralization through blockchain, a new era of secure data management is possible. Blockchain, with its inherent security features, ensures that data stored is secure, difficult to damage or lose due to mutual consensus. Every transaction is recorded, making it easy to carry out the audit process. Therefore, this research will design and implement prototype dApps for secure population management, leveraging the superior security of blockchain technology. The initial stage of research is to conduct a literature study. Furthermore, it is to create designs such as system, infrastructure, and activity diagrams. Then do the development of the dApps prototype. The last is testing using OWASP ZAP and cost analysis. A dApps prototype was implemented on a blockchain. Every transaction is recorded and publicly viewable through the Etherscan platform. Other data stored on a blockchain have gone through an AES-256 encryption process with the data owner's account key so that the owner can only see the data. The results of the tests performed show that there is no high-level warning. The cost analysis results show that the most used costs are when deploying smart contracts and making new data. For further development, it is implementing permissionless blockchain and multi-accounts.

Decentralized Chatting Application Using Blockchain Technology

Abstract: The emergence of blockchain technology has spurred innovation in various domains, including decentralized communication systems. In this context, a decentralized chat application leveraging blockchain, Remix Ethereum IDE, Ganache blockchain, and MetaMask offers a novel approach to secure and privacy-centric messaging. The application harnesses blockchain's immutable ledger to store chat messages, ensuring data integrity and censorship resistance. Remix Ethereum IDE provides developers with a robust environment for crafting smart contracts, the backbone of the chat application's functionality. Developers can design and deploy smart contracts defining chatroom logic, message encryption, and user authentication. Ganache blockchain serves as a local testing environment, enabling developers to validate smart contracts and simulate blockchain interactions in a controlled setting. This facilitates rapid iteration and debugging during the development phase. MetaMask acts as the gateway for users to access the decentralized chat application. Through MetaMask, users authenticate securely using their Ethereum wallets, ensuring pseudonymous identity verification and enabling seamless interaction with the Ethereum blockchain. Together, these technologies form the foundation of a decentralized chat application that prioritizes privacy, security, and user control. By leveraging blockchain and associated tools, the application offers a compelling alternative to centralized messaging platforms, empowering users with sovereignty over their data and communication.

Digital twins and dynamic NFTs for blockchain-based crowdsourced last-mile delivery

In this paper, we propose a blockchain-based crowdsourcing framework leveraging Digital Twins (DTs) and dynamic Non-Fungible Tokens (NFTs) for a transparent last-mile delivery. Existing works propose package delivery through crowdsourced workers managed by centralized or blockchain-based platforms. While the centralized platforms suffer from data security and reliability vulnerabilities, the blockchain-based platforms lack real-time and transparent package status monitoring. The availability of immediate access to status updates and early warnings regarding package storage conditions greatly contributes to ensuring the safe delivery of sensitive packages and preventing spoilage or further damage. As a solution, we propose a decentralized crowdsourcing platform for last-mile delivery utilizing Ethereum smart contracts and DTs for both the packages and the workers. The contracts are leveraged to facilitate interactions between the requesters and workers, and securely execute the task allocation mechanism, which relies on a computed Quality-of-Service (QoS) metric. The package DTs are proposed to oversee the package status and promptly alert workers’ DTs when delivery conditions are violated. To ensure data integrity and prevent malicious alterations, the DTs’ data is securely stored using NFTs. Upon task completion, a calculated Quality-of-Delivery (QoD) acts as a feedback loop in updating workers’ reputations. The proposed allocation mechanism is benchmarked against distance-based and preferences-based allocation mechanisms where our framework improves the average QoS by 76%, average QoD by 22%, and quality of selected workers by 11%. In addition, the DTs are implemented to verify alert generation through a use case. We provide a detailed cost analysis of deployed smart contracts, along with insights into current limitations and proposed mitigation strategies.

GethReplayer: a smart contract testing method based on transaction replay

PurposeSmart contracts are written in high-level programming languages, compiled into Ethereum Virtual Machine (EVM) bytecode, deployed onto blockchain systems and called with the corresponding address by transactions. The deployed smart contracts are immutable, even if there are bugs or vulnerabilities. Therefore, it is critical to verify smart contracts before deployment. This paper aims to help developers effectively and efficiently locate potential defects in smart contracts.Design/methodology/approachGethReplayer, a smart contract testing method based on transaction replay, is proposed. It constructs a parallel transaction execution environment with two virtual machines to compare the execution results. It uses the real existing transaction data on Ethereum and the source code of the tested smart contacts as inputs, conditionally substitutes the bytecode of the tested smart contract input into the testing EVM, and then monitors the environmental information to check the correctness of the contract.FindingsExperiments verified that the proposed method is effective in smart contract testing. Virtual environmental information has a significant effect on the success of transaction replay, which is the basis for the performance of the method. The efficiency of error locating was approximately 14 times faster with the proposed method than without. In addition, the proposed method supports gas consumption analysis.Originality/valueThis paper addresses the difficulty that developers encounter in testing smart contracts before deployment and focuses on helping develop smart contracts with as few defects as possible. GethReplayer is expected to be an alternative solution for smart contract testing and provide inspiration for further research.

Load Balancing in Blockchain Networks: A Survey

Load Balancing (LB) in networking attempts to minimize the under-utilization and over-utilization of network resources by distributing the network flows evenly in the communication network. Blockchain includes a string of joined blocks that are built into the preservation of the non-tampering nature and safeguarding the verifiability. According to our felt experience, we are the initiators to review on blockchain-driven LB, where we organize the blockchain-driven LB concept under 7 categories and interpret thoroughly their performance in relation to LB techniques, BC-driven variables, LB approach, network variables, and similar things. We accumulated an early sample of 76 paper citations by handpicking articles for eligibility requirements scrutinized from web repositories, deploying a thorough and continuous method. Relying on this assessment, blockchain has been deployed in network LB for protecting data fidelity, trustworthiness, confidentiality of data transfers, deploying blockchain consensus for LB, deploying smart contracts for LB, deploying with secure resource trading, access control, and as a coordinator in the system of LB. Moreover, LB involves balancing loads in the blockchain transactions themselves. Thorough interpretation depicts that from blockchaindriven LB schemes, 37.5% deploy blockchain transaction LB, 90% deploy conventional blockchain architecture, 30% deploy generic consensus, 97.5% deploy decentralized LB, 97.5% deploy dynamic LB, 52.5% deploy deterministic LB, and the majority target generic networks. Finally, we go over the potential and predicaments of the notion of blockchain-driven LB and then provision ideas to defeat them.

Penetration Testing Analysis: Impact on Smart Contract Market Value

This study focuses on specifically looking at how penetration testing affects the market value of smart contracts. This study uses a web-based IDE to deploy smart contracts, and it performs penetration testing utilizing reentrancy and delegatecall attacks. The targeted smart contract is exposed to potential exploitation as a result of the assaults' successful implementation. This study shows that penetration testing indirectly affects token prices since incorrect parameter selection and successful attacks might cause changes in token prices. The results emphasize how critical it is to find and fix smart contract vulnerabilities in order to reduce risks and potential losses.

Securing Deployed Smart Contracts and DeFi With Distributed TEE Cluster

Smart contract technologies can be used to implement almost arbitrary business logic. They can revolutionize many businesses such as payments, insurance, and crowdfunding. The resulting birth of decentralized finance (DeFi) has gained significant momentum. Smart contracts and DeFi are now attractive targets for attacks. An important research question is how to protect deployed smart contracts and DeFi. Smart contracts cannot be modified once deployed, namely vulnerabilities cannot be fixed by patching. In this case, vulnerabilities in deployed contracts and DeFi might cause devastating consequences. In this paper, we put forward SolSaviour, a framework for protecting deployed smart contracts and DeFi. The core of SolSaviour is to build a smart contract protection mechanism based on democratic voting using a distributed trusted execution environment (TEE) cluster. Once a vulnerability in deployed contracts or DeFi is found, SolSaviour can destroy the defective contract and redeploy a patched contract via the distributed TEE cluster. Moreover, SolSaviour can migrate funds and state variables from the destroyed contract to the patched one. Compared with previous work, our approach can protect smart contracts and DeFi in a distributed manner, avoiding reliance on privileged users or trusted third parties. Our experiment results show that SolSaviour can protect smart contracts and complex DeFi protocols with feasible overhead.

Blockchain-Driven Real-Time Incentive Approach for Energy Management System

In the current era, the skyrocketing demand for energy necessitates a powerful mechanism to mitigate the supply–demand gap in intelligent energy infrastructure, i.e., the smart grid. To handle this issue, an intelligent and secure energy management system (EMS) could benefit end-consumers participating in the Demand–Response (DR) program. Therefore, in this paper, we proposed a real-time and secure incentive-based EMS for smart grid, i.e., RI-EMS approach using Reinforcement Learning (RL) and blockchain technology. In the RI-EMS approach, we proposed a novel reward mechanism for better convergence of the RL-based model using a Q-learning approach based on the greedy policy that guides the RL-agent for faster convergence. Then, the proposed RI-EMS approach designed a real-time incentive mechanism to minimize energy consumption in peak hours and reduce end-consumers’ energy bills to provide incentives to the end-consumers. Experimental results show that the proposed RI-EMS approach induces end-consumer participation and increases customer profitabilities compared to existing approaches considering the different performance evaluation metrics such as energy consumption for end-consumers, energy consumption reduction, and total cost comparison to end-consumers. Furthermore, blockchain-based results are simulated and analyzed with the help of deployed smart contracts in a Remix Integrated Development Environment (IDE) with the parameters such as transaction efficiency and data storage cost.

Delivery Management System based on Blockchain, Smart Contracts and NFT: A Case Study in Vietnam

Current traditional shipping models are increas-ingly revealing many shortcomings and affecting the interests of sellers and buyers due to having to depend on trusted third parties. For example, the Cash-on-Delivery (CoD) model must depend on the carrier/shipper, or the Letter-of-Credit (LoC) model depends on the place of the Letter certification (i.e., bank). There have been many examples demonstrating the riskiness of the two models above. Specifically, in developing countries (e.g., Vietnam), the demand for exporting goods and trading between sellers and buyers have not yet applied the benefits of current technology to improve traditional shipping models. Two typical examples in the last five years that have demonstrated the risks of both sellers and buyers when applying CoD and LoC models are the problem of keeping the money of the seller of GNN Expresses (2017) as well as risks in losing control of 4 containers of cashew nuts when exporting from Vietnam to Italy (2021). A series of studies have proposed solutions based on distributed storage, blockchain, and smart contracts to solve the above problems. However, the role of the shipper has not been considered in some approaches or is not suitable for deployment in a developed country (i.e., Vietnam). In this paper, we propose a combination model between the traditional CoD model and blockchain technology, smart contracts, and NFT to solve the above problems. Specifically, our contribution includes four aspects: a) proposing a shipping model based on blockchain technology and smart contracts; b) proposing a model for storing package information based on Ethereum’s NFT technology (i.e. ERC721); c) implementing the proposed model by designing smart contracts that support the creation and transfer of NFTs between sellers and buyers; d) deploy smart contracts on four EVM-enabled platforms including BNB Smart chain, Fantom, Celo, and Polygon to find a suitable platform for the proposed model.

A Novel Epoch-Based Transaction Consistency Sorting Protocol for DAG Distributed Ledger

Because of the characteristics of decentralization, immutability, and transparency, blockchain has gradually become a new and revolutionary technology, which has far-reaching significance for the development of modern technology. However, the traditional Bitcoin blockchain that supports synchronous consensus suffers from the fatal flaw of low throughput. To improve throughput, a number of DAG distributed ledgers have been proposed that support asynchronous consensus, all of which allow multiple nodes to process concurrent transactions asynchronously. However, most DAG distributed ledgers do not implement consistent sorting of transactions, making it difficult to deploy smart contracts. To overcome this problem, in this paper, an epoch-based transaction consistency sorting protocol for DAG distributed ledger is proposed, which not only provides the possibility for the deployment of smart contracts but also can be used to resolve conflicting transactions in the ledger. Transaction consistency sorting protocol provides a more reasonably ordered list of all transactions by taking scalars, such as the set of their own past and future, parent block, and timestamp. In addition, through theoretical analysis, the stability and rationality of the transaction consistency sorting protocol are proved, and there is no Condorcet cycle. Finally, the simulation results demonstrate the protocol is efficient and achieve a throughput of at least 2000 transactions per second.

Visualization of blockchain-based smart contracts for delivery, acceptance, and payment process using BIM

Building Information Modeling (BIM) provides an excellent opportunity to digitally document and visually display construction projects’ information throughout their whole lifecycle. Another recent technology that fosters the digital transformation of the construction sector is blockchain-based smart contract. In combination with BIM models, such smart contract can be used for delivery, acceptance, and payment (DAP) process automation in the construction industry. The DAP process can be modelled by using smart contracts and securely stored via a blockchain. Since smart contracts are programming codes, for stakeholders it is difficult to understand what is exactly written in them. Therefore, it is necessary to visualize the state and executed transactions of the deployed smart contracts. In this paper, a framework is highlighted to record and visualize the status of the DAP processes by combining BIM with smart contracts using the Business Process Model and Notation (BPMN) to develop a smart contract system. With the help of suitable visualization concepts, the individual transactions of the blockchain can be displayed in a comprehensible way. The feasibility of the framework is presented through an illustrative implementation of the smart contract system. The proposed framework can help project participants better understand the current state of a smart contract.

Blockchain Meets Sharing Economy: A Case of Smart Contract Enabled Ridesharing Service

The ideas of the sharing economy have facilitated innovative business applications, such as Uber and Airbnb. As an example of a sharing economy application, ridesharing services take advantage of underutilized resources to create economic value. However, the unruly design of ridesharing systems may make urban traffic more congested and cause other technology-organization-environment issues. This study explores the application of blockchain and smart contract technologies to enhance ridesharing services by harvesting the blockchain benefits of transaction traceability, process transparency, system automation and disintermediation. After presenting system design and implementation details for building and deploying a blockchain-based system to support the reengineered ridesharing service with required business functions, we conduct functionality/performance tests and theory-based comparative analysis to confirm its feasibility and applicability. The results reveal that our system with blockchain-enabled benefits is superior to incumbent ridesharing systems. Moreover, while prior research rarely reports the design and implementation details of blockchain-based systems to support sharing economy services, this paper primarily contributes to extant literature by not only proposing a layered system architecture adapting blockchain and smart contracts into the desired ridesharing service but also demonstrating the design and implementation details, covering the development tools, the deployment environment and the deployed smart contracts.

A privacy-preserving blockchain-based tracing model for virus-infected people in cloud

The outbreak of COVID-19 has exposed the privacy of positive patients to the public, which will lead to violations of users’ rights and even threaten their lives. A privacy-preserving scheme involving virus-infected positive patients is proposed by us. The traditional ciphertext policy attribute-based encryption (CP-ABE) has the features of enhanced plaintext security and fine-grained access control. However, the encryption process requires the high computational performance of the device, which puts a high strain on resource-limited devices. After semi-honest users successfully decrypt the data, they will get the real private data, which will cause serious privacy leakage problems. Traditional cloud-based data management architectures are extremely vulnerable in the face of various cyberattacks. To address the above challenges, a verifiable ABE scheme based on blockchain and local differential privacy is proposed, using LDP to perturb the original data locally to a certain extent to resist collusion attacks, outsourcing encryption and decryption to corresponding service providers to reduce the pressure on mobile terminals, and deploying smart contracts in combination with blockchain for fair execution by all parties to solve the problem of returning wrong search results in a semi-honest cloud server. Detailed security proofs are performed through the defined security goals, which shows that the proposed scheme is indeed privacy-protective. The experimental results show that the scheme is optimized in terms of data accuracy, computational overhead, storage performance, and fairness. In terms of efficiency, it greatly reduces the local load, enhances personal privacy protection, and has high practicality as well as reliability. As far as we know, it is the first case of applying the combination of LDP technology and blockchain to a tracing system, which not only mitigates poisoning attacks on user data, but also improves the accuracy of the data, thus making it easier to identify infected contacts and making a useful contribution to health prevention and control efforts.

EDALoCo: Enhancing the accessibility of blockchains through a low-code approach to the development of event-driven applications for smart contract management

Blockchain is a cutting-edge technology based on a distributed, secure and immutable ledger that facilitates the registration of transactions and the traceability of tangible and intangible assets without requiring central governance. The agreements between the nodes participating in a blockchain network are defined through smart contracts. However, the compilation, deployment, interaction and monitoring of these smart contracts is a barrier compromising the accessibility of blockchains by non-expert developers. To address this challenge, in this paper, we propose a low-code approach, called EDALoCo, that facilitates the development of event-driven applications for smart contract management. These applications make blockchain more accessible for software developers who are non-experts in this technology as these can be modeled through graphical flows, which specify the communications between data producers, data processors and data consumers. Specifically, we have enhanced the open-source Node-RED low-code platform with blockchain technology, giving support for the creation of user-friendly and lightweight event-driven applications that can compile and deploy smart contracts in a particular blockchain. Additionally, this platform extension allows users to interact with and monitor the smart contracts already deployed in a blockchain network, hiding the implementation details from non-experts in blockchain. This approach was successfully applied to a case study of COVID-19 vaccines to monitor and obtain the temperatures to which these vaccines are continuously exposed, to process them and then to store them in a blockchain network with the aim of making them immutable and traceable to any user. As a conclusion, our approach enables the integration of blockchain with the low-code paradigm, simplifying the development of lightweight event-driven applications for smart contract management. The approach comprises a novel open-source solution that makes data security, immutability and traceability more accessible to software developers who are non-blockchain experts.

A Low-Cost, Open-Source Peer-to-Peer Energy Trading System for a Remote Community Using the Internet-of-Things, Blockchain, and Hypertext Transfer Protocol

A low-cost, open-source peer-to-peer (P2P) energy trading system for a remote community is presented in this paper. As a result of its geographic location, this community has never been able to access electricity and other modern amenities. This study aims to design and implement a P2P energy trading system for this remote community that allows residents to take advantage of distributed energy resources. A Raspberry Pi 4 Model B (Pi4B) hosts the main server of the trading system that includes the user interface and a local Ethereum blockchain server. The Ethereum blockchain is used to deploy smart contracts. The Internet-of-Things (IoT) servers run on ESP32 microcontrollers. Sensors and actuators connected to the ESP32 are field instrumentation devices that facilitate acquiring, monitoring, and transferring energy data in real-time. To perform trading activities, React.JS open-source library was used to develop the blockchain-enabled user interface. An immutable blockchain network keeps track of all transactions. The proposed system runs on a local Wi-Fi network with restricted authorization for system security. Other security measures such as login credentials, private key, firewall, and secret recovery phrases are also considered for information security and data integrity. A Hypertext Transfer Protocol is implemented for communication between the servers and the client. This explains the overall system design, implementation, testing, and results.

A Secure and Privacy-Preserving Medical Data Sharing via Consortium Blockchain

Medical data sharing is of great significance in promoting smart medicine. However, the heterogeneity of information systems used by various medical institutions makes sharing difficult. In addition, since medical data involves a great deal of sensitive information, sharing it could easily lead to the leakage of personal privacy. Blockchain, gained popularity as a distributed ledger technology, has great potential to connect heterogeneous systems and provides authenticity and integrity guarantees for medical data sharing. Focusing on the issues of medical data sharing and privacy protection, we propose a medical data sharing scheme based on consortium blockchain. To achieve access control, attribute-based access control technique is implemented, where patients preset attribute-specific access policies for their medical records, and record requesters are described by a set of attributes. For patients, we devise a hybrid storage mode to write access policies of medical records on the consortium blockchain network and store encrypted medical records off-chain. Leveraging blockchain and smart contracts, access privilege control and access history tracking can be realized. To enhance the key management, a tree of medical records is constructed for each patient, and by simply keeping the medical record trees, patients can recover their encryption keys at any time. Furthermore, we carry out an extensive analysis to show the high security and efficiency of our proposed scheme. Finally, we build a Quorum consortium blockchain on the Tencent Cloud and deploy smart contracts on the chain to simulate transactions in our scheme. The experiment results indicate the proposed scheme achieves good feasibility.

Decentralized Web Application for Real Estate Property Transaction using Blockchain and Smart Contract Technology

Real Estate is a wide area consisting of a physical piece of land and the developments on it such as buildings, roads, and other infrastructures. Real Estate can be classified based on the purpose of usage of the property i.e. Residential, Commercial, or Industrial. Since longtime real estate is considered the most secure investment for good returns. But several issues arise in the field of property transactions which are based on the trust that the buyer or seller has in a third-party middleman/broker as well as frauds, inaccurate market statistics, time-consuming processes as well as high processing fees charged by the middlemen/broker. To provide a solution problem a decentralized web application for real estate transactions is proposed in the project. To attain the solution, in this project we propose to design and develop a decentralized web application using blockchain and smart contract technology that avails property buyers and sellers to interact with the help of a private Ethereum network and deploy smart contracts which create a precise and transparent digital property transaction process. This results in the advantages over traditional real estate systems by neglecting the requirement of non-trusted third-party entities, reducing transaction processes as well as transaction costs.

Data Integrity Audit Scheme Based on Blockchain Expansion Technology

Increasing numbers of users are outsourcing data to the cloud, but data integrity is an important issue. Due to the decentralization and immutability of blockchain, more and more researchers tend to use blockchain to replace third-party auditors. This paper proposes a data integrity system based on blockchain expansion technology that aims to solve the problem of high cost for blockchain network maintenance and for user creation of new blocks caused by the rapid growth of blocks in the data integrity audit scheme of existing blockchain technology. Users and cloud service providers (CSP) deploy smart contracts on the main chain and sub-chains. Intensive and frequent computing work is transferred to the sub-chain for completion, and the computation results of the sub-chain are submitted to the main chain periodically or when needed to ensure its finality. The concept of non-interactive audit is introduced to avoid affecting user experience due to the communication with the CSP during the audit process. In order to ensure data security, a reward pool mechanism is introduced. Comprehensive analysis from aspects such as storage, batch auditing and data consistency proves the correctness of the scheme. Experiments on the Ethereum blockchain platform demonstrate that this scheme can effectively reduce storage and computational overhead.

Do-It-Yourself Recommender System: Reusing and Recycling With Blockchain and Deep Learning

Due to aggressive urbanization (with population size), waste increases exponentially, resulting in environmental damage. Even though it looks challenging, such an issue can be controlled if we can reuse them. To handle this, in our work, we design a machine learning and blockchain-oriented system that identifies thewaste objects/products and recommends to the user multiple ’Do-It-Yourself’ (DIY) ideas to reuse or recycle. Blockchain records every transaction in the shared ledger to enable transaction verifiability and supports better decision-making. In this study, a Deep Neural Network (DNN) trained on about 11700 images is developed using ResNet50 architecture for object recognition (training accuracy of 94%).We deploy several smart contracts in the Hyperledger Fabric (HF) blockchain platform to validate recommended DIY ideas by blockchain network members. HF is a decentralized ledger technology platform that executes the deployed smart contracts in a secured Docker container to initialize and manage the ledger state. The complete model is delivered on a web platform using Flask, where our recommendation system works on a web scraping script written using Python. Fetching DIY ideas using web-scraping takes nearly 1 second on a desktop machine with an Intel Core-i7 processor with 8 cores, 16 GB RAM, installed with Ubuntu 18.04 64-bit operating system, and Python 3.6 package. Further, we evaluate blockchain-based smart contracts’ latencies and throughput performances using the hyperledger caliper benchmark. To the best of our knowledge, this is the first work that integrates blockchain technology and deep learning for the DIY recommender system.