Izdehar M. Aldyaflah, Wenbing Zhao, Himanshu Upadhyay, Leonel Lagos
In this paper, we present a secure datastore based on an Ethereum smart contract. Our research is guided by three research questions. First, we will explore to what extend a smart-contract-based datastore should resemble a traditional database system. Second, we will investigate how to store the data in a smart-contract-based datastore for maximum flexibility while minimizing the gas consumption. Third, we seek answers regarding whether or not a smart-contract-based datastore should incorporate complex processing such as data encryption and data analytic algorithms. The proposed smart-contract-based datastore aims to strike a good balance between several constraints: (1) smart contracts are publicly visible, which may create a confidentiality concern for the data stored in the datastore; (2) unlike traditional database systems, the Ethereum smart contract programming language (i.e., Solidity) offers very limited data structures for data management; (3) all operations that mutate the blockchain state would incur financial costs and the developers for smart contracts must make sure sufficient gas is provisioned for every smart contract call, and ideally, the gas consumption should be minimized. Our investigation shows that although it is essential for a smart-contract-based datastore to offer some basic data query functionality, it is impractical to offer query flexibility that resembles that of a traditional database system. Furthermore, we propose that data should be structured as tag-value pairs, where the tag serves as a non-unique key that describes the nature of the value. We also conclude that complex processing should not be allowed in the smart contract due to the financial burden and security concerns. The tag-based secure datastore designed this way also defines its applicative perimeter, i.e., only applications that align with our strategy would find the proposed datastore a good fit. Those that would rather incur higher financial cost for more data query flexibility and/or less user burden on data pre- and post-processing would find the proposed database too restrictive.
P. Hari Babu, J. Anusha, J. Jaya Prakash, Ch. Krishna Veni · 5 authors
Trust is the main barrier preventing widespread data sharing. The lack of transparent infrastructures for implementing data trust prevents many data owners from sharing their data and concerns data users regarding the quality of the shared data. Blockchain technology proposes a distributed and transparent administration by employing multiple parties to maintain consensus on an immutable ledger. This project presents an end-to-end framework for data trust to enhance trustworthy data sharing utilizing blockchain technology. We also suggest an adaptive solution to determine the number of transaction validators based on the computed trust value.
Ayei E. Ibor, Edim Bassey Edim, Arnold Adimabua Ojugo
This paper focuses on highlighting the problems that are associated with the absence of privacy and security of medical records in a healthcare system. It seeks to bridge the gap between the currently used security protocols in the management of health information, and encryption algorithms that should be used. Extant health information systems have always been developed with conventional databases. With all the privileges to read, write and execute assigned to the administrator, who has centralised control over all medical records, there is the likelihood of the misuse, distortion and loss of such records in the event that the administrator becomes compromised or inadvertent system failure. To solve this problem, the use of decentralised and distributed databases becomes paramount. Blockchain technology has recently received much attention due to its ability to permit a peer-to-peer network with distributed databases that can be stored locally on each node in the network. Subsequently, all updates on records in a database are communicated to all participating parties, hence addressing the problem of centralised control. In this paper, we propose a health information system on a blockchain to create a trust-free system for both health personnel and patients. From the results obtained, we achieved the decentralisation of the medical records’ database to enhance the security and privacy of data on the modeled peer-to-peer network.
Distributed computing is a business and monetary model permitting the clients to use top of the line registering and stockpiling practically with insignificant foundation on their end. In current medical care frameworks, electronic clinical records (EMRs) are modernized records which contains rundown of insights about patients wellbeing. Electronic clinical records are compelling contrasted with the current traditional stockpiling approaches because of its unified stockpiling of information, it prompts weak link as patients being the genuine proprietor forget about their private and delicate EMRs. Distributed computing utilizing encryption calculation is one of the critical figure the clinical administration framework which permits the clients to get to the wellbeing subtleties of patients in the safeguarded manner. The proposed work is to fabricate an encoded admittance control structure, contrasting the different encryption calculations accessible and utilize the most ideal calculation to get the sharing of EMRs among various elements associated with the shrewd medical services framework. Keywords- Medical Care; Electronic Clinical Records
Farooq Sunar Mahammad, S. Sai Shreya, H. Beebe Hazeera, P. Sravani · 6 authors
Decentralized Application is majorly used for sharing the most important information of the students' among various users.Blockchain technology is used to address security concerns associated with students' credential sharing.A revolutionary blockchain-based architecture is proposed, and the application is then built as a distributed one (DApp).In order to avoid the counterfeiting of the students' credentials the features of block chain technology are more widely used.This application is used to share the credentials of the student by the college/school directly to student and those data can be used by the companies those who recruit students can directly access students' data by getting the permission from students' without any third-party involvement, this saves time and money.Ethereum framework is used to create an application in which Truffle framework is used to make the developer's life easier by creating smart contracts and has the migration and uses web3.js as it is beginner friendly.Furthermore, the results of the tests are used to analyses both costs and efficiency.
• A distributed data integrity verification method without third-party auditor is proposed. Based on the constructed hashTable, each hospital server can audit the data in a distributed manner. • A blockchain-based auditing scheme is designed for cloud-edge healthcare system, which includes the consensus protocol Proof of Auditing Frequency (PoAF) and related block structures. • The proposed scheme is evaluated against two start-of-the-art schemes in a simulated cloud-edge healthcare system and comprehensively evaluated. Cloud-edge healthcare system provides storage and computing functions at the hospital servers, bringing low latency for doctors and patients. However, hospital servers cannot be trusted and have limited computing resources. Data integrity verification for the cloud-edge healthcare system is an urgent concern. To this end, we proposed a data integrity auditing scheme based on blockchain. First, a distributed data integrity verification method without a third-party auditor is designed. The data are divided into smaller parts and hashed into a hash table. The verification tag is constructed according to the column of the hash table and secret string generated by a pseudo-random function. Then, a detailed blockchain-based data integrity auditing scheme is proposed, including Proof of Auditing Frequency and block structure. Besides, a security analysis for the common attacks is given. Finally, the proposed scheme is evaluated against two start-of-the-art schemes in a simulated cloud-edge healthcare system. The results demonstrate that the proposed scheme can verify data integrity without losing efficiency.
<p>The first cryptocurrency was invested in 2008/09, but the Blockchain-Web3 concept is still in its infancy, and the cyber risk is constantly changing. Our cybersecurity should also be adapting to these changes to ensure security of personal data and continuation of business for organisations. This review paper starts with a comparison of existing cybersecurity standards and regulations from the National Institute of Standards and Technology (NIST) and the International Organization for Standardization (ISO) - ISO27001, followed by a discussion on more specific and recent standards and regulations, such as the Markets in Crypto-Assets Regulation (MiCA), Committee on Payments and Market Infrastructures and the International Organisation of Securities Commissions (CPMI-IOSCO), and more general cryptography and post-quantum cryptography, in the context of cybersecurity. These topics are followed up by a review of recent technical reports on cyber risk/security and a discussion on cloud security questions. Comparison of Blockchain cyber risk is also performed on the recent EU standards on cyber security, including European Cybersecurity Certification Scheme (EUCS) – cloud, and additional US standards – The National Vulnerability Database (NVD) Common Vulnerability Scoring System (CVSS). The study includes a review of Blockchain endpoint security, and new technologies e.g., IoT. The research methodology applied is a review and case study analysing secondary data on cybersecurity. The research significance is the integration of knowledge from the United States (US), the European Union (EU), the United Kingdom (UK), and international standards and frameworks on cybersecurity that can be alighted to new Blockchain projects. The results show that cybersecurity standards are not designed in close cooperation between the two major western blocks - US and EU. In addition, while the US is still leading in this area, the security standards for cryptocurrencies, internet-of-things, and blockchain technologies have not evolved as fast as the technologies have. The key finding from this study is that although the crypto market has grown into a multi-trillion industry, the crypto market has also lost over 70% since its peak, causing significant financial loss for individuals and cooperation’s. Despite this significant impact to individuals and society, cybersecurity standards and financial governance regulations are still in their infancy.</p>
Ring Confidential Transactions (RingCT) is a protocol associated with the privacy-focused cryptocurrency Monero and is used to hide the transaction amount from the third party while still providing the confidentiality of the hide transaction. With the Pederson commitment scheme, ring signature, and other cryptographic constructions, RingCT plays a major role in making the transactions of Monero private. As a privacy coin, Monero has the unique property of fungibility in the cryptocurrency market from the protocols implemented. These protocols provided opportunities and challenges for its future. In this paper, the version of the protocol implemented in Monero is first inspected, including the commitment to zero and the range proof. Then, two critical cryptographic constructions used by RingCT 2.0, the accumulator and the signature of knowledge, are introduced. Finally, the influence of RingCT and other privacy features and the current situation of privacy coin is discussed.
Ethereum digital signatures have been found to make progress, but there has yet to be a consensus regarding their significance and process. Using digital signatures in Ethereum ensures the security of users' money and the Safety of their transportation. Elliptic Curve Digital Signature Algorithm (ECDSA), private key, and public key play an important role here. This paper analyzes the details of Ethereum's Digital Signature based on existing information. First, it explained the general background information about Ethereum. Send explain the ERC-20. ERC-20 are digital assets that represent value. They could become more compatible with the new standard and allow other features. Then digital signatures are explained in detail. This part included ECDSA, private key, and public key. ECDSA is the most critical algorithm during the production process. Private and public keys are the key features to ensure Safety. The last part is the Keystore file system. Using the Keystore file system, users can secure their private keys for their cryptocurrency wallets. To access their account, the user must have a password generated by them. The unencrypted files, on the other hand, create a vulnerability in the key store, which is exposed by these unencrypted files. Once an attacker obtains the user's unencrypted key, he cannot only take control of the account but also sign transactions on behalf of the user.
Blockchain is a decentralized, shared ledger that aggregates blocks of data in a factual data structure in chronological order using a chain structure. Two hundred sixty thousand tokens, or 98% of the around 2.5 million smart contracts in Ethereum network, are ERC-20 tokens. The ERC20 standard specifies constructors for token contracts that establish and initialize the contract state. The Ethereum wallet and Ethereum decentralized, centralized applications can access tokens through these standard interfaces. Security vulnerabilities in ERC-20 have drawn a lot of attention lately in recent years. This paper summarizes some basic security vulnerabilities and suggests avoiding multiple withdrawal attacks. Tokens can be used to support dApps, access blockchain services, trade, and obtain voting rights. Various tokens exist depending on their properties and use cases, including governance, utility, security, transaction, and platform tokens. Tokens can be sorted as fungible tokens and non-fungible tokens. Tokens that can be fungible are identical, divisible, and can be instead of money. Non-fungible tokens have a single owner and are unique.
Multi-party business processes rely on the collaboration of various players in a decentralized setting. Blockchain technology can facilitate the automation of these processes, even in cases where trust among participants is limited. Transactions are stored in a ledger, a replica of which is retained by every node of the blockchain network. The operations saved thereby are thus publicly accessible. While this enhances transparency, reliability, and persistence, it hinders the utilization of public blockchains for process automation as it violates typical confidentiality requirements in corporate settings. In this paper, we propose MARTSIA: A Multi-Authority Approach to Transaction Systems for Interoperating Applications. MARTSIA enables precise control over process data at the level of message parts. Based on Multi-Authority Attribute-Based Encryption (MA-ABE), MARTSIA realizes a number of desirable properties, including confidentiality, transparency, and auditability. We implemented our approach in proof-of-concept prototypes, with which we conduct a case study in the area of supply chain management. Also, we show the integration of MARTSIA with a state-of-the-art blockchain-based process execution engine to secure the data flow.
Everything is digitalized in the digital age, including the SSLC, HSC, and academic certificates, which are sent to students and digitalized at educational establishments. Students have difficulty maintaining their degree credentials. Organizations and institutions find it difficult and time-consuming to verify certificates. By storing the certificate in the Blockchain system, our proposal will aid in its security. Advanced certificates are first made from the paper certificates. The certificate's hash code esteem is made utilizing the turbulent calculation. From that point onward, the confirmations are saved in Blockchain. Moreover, these certificates are confirmed through the versatile application.
Closed-circuit television (CCTV) cameras and black boxes are indispensable for road safety and accident management. Visible highway surveillance cameras can promote safe driving habits while discouraging moving violations. According to CCTV laws, footage captured by roadside cameras must be securely stored, and authorized persons can access it. Footages collected by CCTV and Blackbox are usually saved to the camera’s microSD card, the cloud, or hard drives locally but there are concerns about security and data integrity. These issues may be addressed by blockchain technology. The cost of storing data on the blockchain, on the other hand, is prohibitively expensive. We can have decentralized and cost-effective storage with the interplanetary file system (IPFS) project. It is a file-sharing protocol that stores and distributes data in a distributed file system. We propose a decentralized IPFS and blockchain-based application for distributed file storage. It is possible to upload various types of files into our decentralized application (DApp), and hashes of the uploaded files are permanently saved on the Ethereum blockchain with the help of smart contracts. Because it cannot be removed, it is immutable. By clicking on the file description, we can also view the file. DApp also includes a keyword search feature to assist us in quickly locating sensitive information. We used Ethers.js’ smart contract event listener and contract.queryFilter to filter and read data from the blockchain. The smart contract events are then written to a text file for our DApp’s keyword search functionality. Our experiment demonstrates that our DApp is resilient to system failure while preserving the transparency and integrity of data due to the immutability of blockchain.
Umair B. Chaudhry, Aysha Kattakath Mulangat Hydros
Abstract Cyber security in the banking sector is of high importance nowadays. The rate of cyberattacks is spiking every year, and the implementation of strong cybersecurity models is required to ensure the confidentiality and integrity of data. Since protecting a bank requires a wide range of security practices, this paper focuses on protecting the bank resources from malicious actors and securing the transactions using a blockchain consensus mechanism that uses a zero‐trust security approach among the participants in the transaction. In addition to the framework, an algorithm for blockchain‐based online transactions was designed to make use of practical implementation in the future. The ideas formulated during the research and literature review were integrated to design the framework and the algorithm. The proposed framework ensures that the security of the banking sector can be enhanced by adopting the zero‐trust concept and blockchain technology. The consensus algorithms used for the transaction make it immutable and decentralized. Zero‐trust principles adopted in the model ensure the confidentiality and integrity of the banking system.
P D Prakruthi, K Yashawanth, D. L. Chethan, Bhuvan Kumar · 7 authors
AWS is an upcoming technology along with decentralized infrastructure. This knowledge is employed in variety of different domains including cloud computing, finance, energy, messaging and others. AWS really takes up vital part in military message passing which enables certainty and safety of messages by dodging changes created to data that is collected in blocks. AWS needs the access where each user is an authorized user. In this paper we will be proposing different cryptographic techniques along with AWS technology to ensure safe and secure passage of messages between different teams in the defence sector.
Shaima AL Amri, Leonardo Aniello, Vladimiro Sassone
The Ethereum blockchain is one of the main public platforms to run smart contracts and enable decentralised applications. Since data stored in a blockchain is considered immutable, smart contracts deployed in Ethereum are regarded as tamper-proof and therefore offer strong protection against attacks aiming at tinkering with the execution flow of an application. Yet, like any other software, a smart contract needs to be maintained over time to fix bugs or add new features. Deploying every updated version as a brand-new smart contract in Ethereum leads to problems such as migrating the contract state from the old version and enabling clients to point to the new version in a timely fashion. The OpenZeppelin framework addresses this limitation by providing libraries that enable the deployment of upgradeable smart contracts. This is achieved by relying on proxies that act as intermediaries between clients and smart contracts, allowing the latter to be updated transparently. In this paper, we present the upgradeable smart contract patterns supported by OpenZeppelin and compare them in terms of security, cost, and performance. To show this paradigm’s prevalence in Ethereum, we also analyse the usage of OpenZeppelin Upgradeable smart contracts over the last four years.
P. Chinnasamy, Ashwag Albakri, Mudassir Khan, A. Ambeth Raja · 6 authors
Healthcare comprises the largest revenue and data boom markets. Sharing knowledge about healthcare is crucial for research that can help healthcare providers and patients. Several cloud-based applications have been suggested for data sharing in healthcare. However, the trustworthiness of third-party cloud providers remains unclear. The third-party dependency problem was resolved using blockchain technology. The primary objective of this growth was to replace the distributed system with a centralized one. Therefore, security is a critical requirement for protecting health records. Efforts have been made to implement blockchain technology to improve the security of this sensitive material. However, existing methods depend primarily on information obtained from medical examinations. Furthermore, they are ineffective for sharing continuously produced data streams from sensors and other monitoring devices. We propose a trustworthy access control system that uses smart contracts to achieve greater security while sharing electronic health records among various patients and healthcare providers. Our concept offers an active resolution for secure data sharing in mobility computing while protecting personal health information from potential risks. In assessing existing data sharing models, the framework valuation and protection approach recognizes increases in the practicality of lightweight access control architecture, low network expectancy, and significant levels of security and data concealment.
Recent advancement in IoT technology has boosted the healthcare domain with enormous usage of IoT devices to provide elevated services to patients with chronic disorders on a real-time basis by the incorporation of IoT sensors on patients’ bodies. However, providing services ensuring security and maintaining the privacy of patients is a challenging task. Blockchain technology promises security in a distributed environment but popular consensus algorithms such as Proof of Work (PoW) and Proof of Stake (PoS) require huge computational resources and energy by making the IoT environment inefficient. This paper introduces a secure Practical Byzantine Fault Tolerance (PBFT) consensus-based lightweight blockchain algorithm for healthcare applications. To strengthen the PBFT consensus, highly trusted nodes were allowed to participate in the consensus algorithm using the Eigen Trust model and Verifiable Random Function (VRF) to select a random primary node from a group of trusted consensus nodes. The proposed algorithm is tested in a simulated environment and evaluated against the traditional PBFT consensus algorithm considering throughput, latency, and fault tolerance.
Linh Thủy Nguyễn, Lam Duc Nguyen, Thong Hoang, H. M. N. Dilum Bandara · 10 authors
The rise of data-sharing platforms, driven by public demand for open data and legislative mandates, has raised several pertinent issues. These encompass uncertainties over data accuracy, provenance and lineage, privacy concerns, consent management, and the lack of equitable incentives for data providers. The advanced nature of blockchain makes it well suited to address these concerns. Yet, the limitations of blockchains, particularly their restricted performance, scalability, and high cost, make them less adept at managing the four “Vs” of big data—volume, variety, velocity, and veracity. As the body of work proposing blockchain-based data-sharing solutions grows, so does the confusion in selecting between these platforms, particularly in terms of sharing mechanisms, services, quality of services, and applications. In this article, we aim to fill this knowledge gap through an in-depth survey of blockchain-based data-sharing architectures and applications. We first identify the key challenges of existing data-sharing techniques and lay out the foundations of blockchains. Our focus then shifts to the intersection of blockchain and data sharing, wherein we aim to clarify the existing landscape and propose a reference architecture for blockchain-based data sharing. Subsequently, we explore various industrial applications of blockchain-based data sharing, spanning healthcare, smart grids, transportation, and decarbonization. For each application, we draw from real-world deployments to present key lessons learned in the implementation of blockchain-based data sharing. Lastly, we shed light on current research challenges and open avenues for further study in this space. This article aims to serve as a comprehensive resource for researchers/practitioners looking to navigate the complex terrain of blockchain-based data-sharing solutions.
Abdul Mateen, Adia Khalid, Sihyung Lee, Seung Yeob Nam
Despite the rapid expansion in the insurance industry, many issues remain unresolved and may require immediate action. As the insurance sector continues to evolve with the development of new technologies, it faces more challenges, especially related to data security and fraud. The fraud-prevention data and tactics presently used by insurance firms are outdated and ineffective. Additionally, insurance firms have traditionally handled the settlement of all consumer claims through lengthy manual processes. These manual processes need to be changed to provide opportunities for insurance businesses to grow. In the case of vehicles, the information obtained from an automobile data recorder can be used as evidence. Data from automated vehicles are critical because they can help the police, law enforcement agencies, and insurance companies to reconstruct the events leading up to a collision. Insurance companies require the forensic analysis of accident videos, which is a time-consuming process and involves a large amount of storage. Due to hardware limitations and associated costs, the current standalone (and often dedicated) computing infrastructures used for this purpose are quite limited. Previous research focused on simple video analysis tasks within cloud computing and blockchain technology. The requirements for a large-scale auto-insurance system are quite high and need more thorough investigation. In this paper, a review of the contribution of recent approaches to storing accidental data in cloud computing using blockchain is provided. We focused on the latest cloud and blockchain studies related to auto-insurance along with the related issues and challenges. Some useful solutions and recommendations are provided to address the identified issues and challenges in the cloud-based and blockchain-based auto-insurance sector.
Yuri Bespalov, Lyudmila Kovalchuk, Hanna Nelasa, Roman Oliynykov · 5 authors
Sidechains are among the most promising scalability and extended functionality solutions for blockchains. Application of zero knowledge techniques (Latus, Mina) allows for reaching high level security and general throughput, though it brings new challenges on keeping decentralization where significant effort is required for robust computation of zk-proofs. We consider a simultaneous decentralized creation of various zk-proof trees that form proof-trees sequences in sidechains in the model that combines behavior of provers, both deterministic (mutually consistent) or stochastic (independent) and types of proof trees. We define the concept of efficiency of such process, introduce its quantity measure and recommend parameters for tree creation. In deterministic cases, the sequences of published trees are ultimately periodic and ensure the highest possible efficiency (no collisions in proof creation). In stochastic cases, we obtain a universal measure of prover efficiencies given by the explicit formula in one case or calculated by a simulation model in another case. The optimal number of allowed provers’ positions for a step can be set for various sidechain parameters, such as number of provers, number of time steps within one block, etc. Benefits and restrictions for utilization of non-perfect binary proof trees are also explicitly presented.
Alexander Bernauer, Sofia Faro, Rémy Hämmerle, Martin Huschenbett · 11 authors
Distributed ledger technologies, also known as blockchains for enterprises, promise to significantly reduce the high cost of automating multi-party business workflows. We argue that a programming language for writing such on-ledger logic should satisfy three desiderata: (1) Provide concepts to capture the legal rules that govern real-world business workflows. (2) Include simple means for specifying policies for access and authorization. (3) Support the composition of simple workflows into complex ones, even when the simple workflows have already been deployed. We present the open-source smart contract language Daml based on Haskell with strict evaluation. Daml achieves these desiderata by offering novel primitives for representing, accessing, and modifying data on the ledger, which are mimicking the primitives of today's legal systems. Robust access and authorization policies are specified as part of these primitives, and Daml's built-in authorization rules enable delegation, which is key for workflow composability. These properties make Daml well-suited for orchestrating business workflows across multiple, otherwise heterogeneous parties. Daml contracts run (1) on centralized ledgers backed by a database, (2) on distributed deployments with Byzantine fault tolerant consensus, and (3) on top of conventional blockchains, as a second layer via an atomic commit protocol.
Justice Odoom, Huang Xiao-fang, Samuel Akwasi Danso, Benedicta Nana Esi Nyarko
Recently, blockchain technology has garnered support. However, an attenuating factor to its global adoption in certain use cases is privacy-preservation owing to its inherent transparency. A widely explored cryptographic option to address this challenge has been ring signature which aside its privacy guarantee must be double spending resistant. In this paper, we identify and prove a catastrophic flaw for double-spending attack in a Lightweight Ring Signature scheme and proceed to construct a new, fortified commitment scheme using the signer’s entire private key. Subsequently, we compute a stronger key image to yield a double-spending-resistant signature scheme solidly backed by formal proof. Inherent in our solution is a novel, zero-knowledge-based, secured and cost-effective smart contract for public key aggregation. We test our solution on a private blockchain as well as Kovan testnet along with performance analysis attesting to efficiency and usability and make the code publicly available on GitHub.
Feruz K. Elmay, Mohammad Madine, Khaled Salah, Raja Jayaraman
The distribution, traceability, and management of shipping container logistics require secure data flow and trusted transactions. Digital Twins (DTs) can realize these features by offering shipping tracking and traceability, process flow and status monitoring, and management of the physical containers all in a remote manner. However, the data of a DT itself is typically stored, controlled, and managed by a centralized entity, which is often the original creator of the physical container. Having a centralized entity can cause mistrust. The centralized entity may alter, tamper, or delete the digital twin data. To overcome this problem, this paper proposes trusted sharing and management of DTs for shipping containers by using Non-Fungible Tokens (NFTs). NFTs are digital tokens that hold unique data stored, controlled, and managed in a decentralized and immutable blockchain ledger. We extend in this paper the use of NFTs to tokenize shipping container DTs and their metadata. The proposed solution uses NFTs and Ethereum blockchain smart contracts to offer decentralization, security, transparency, traceability, and immutability to the data and processes involved in the creation, storage, and management of DTs of shipping containers. To demonstrate our solution, we create a DT of a shipping container using Microsoft Azure Digital Twins services and showed how to tokenize it using NFT. We assess the system using various test cases to evaluate its main functionalities. Furthermore, we analyze the cost of transactions and the security of the smart contracts code. We have made the code of our smart contracts publicly available on GitHub.