Biblio

Blockchain and artificial intelligence are two technologies that, when combined, have the ability to help each other realize their full potential. Blockchains can guarantee the accessibility and consistent admittance to integrity safeguarded big data indexes from numerous areas, allowing AI systems to learn more effectively and thoroughly. Similarly, artificial intelligence (AI) can be used to offer new consensus processes, and hence new methods of engaging with Blockchains. When it comes to sensitive data, such as corporate, healthcare, and financial data, various security and privacy problems arise that must be properly evaluated. Interaction with Blockchains is vulnerable to data credibility checks, transactional data leakages, data protection rules compliance, on-chain data privacy, and malicious smart contracts. To solve these issues, new security and privacy-preserving technologies are being developed. AI-based blockchain data processing, either based on AI or used to defend AI-based blockchain data processing, is emerging to simplify the integration of these two cutting-edge technologies.

The outsourcing of databases is very popular among IT companies and industries. It acts as a solution for businesses to ensure availability of the data for their users. The solution of outsourcing the database is to encrypt the data in a form where the database service provider can perform relational operations over the encrypted database. At the same time, the associated security risk of data leakage prevents many potential industries from deploying it. In this paper, we present a secure outsourcing database search scheme (BASDB) with the use of a smart contract for search operation over index of encrypted database and storing encrypted relational database in the cloud. Our proposed scheme BASDB is a simple and practical solution for effective search on encrypted relations and is well resistant to information leakage against attacks like search and access pattern leakage.

In the smart grid, the sharing of power data among various energy entities can make the data play a higher value. However, there may be unauthorized access while sharing data, which makes many entities unwilling to share their data to prevent data leakage. Based on blockchain and ABAC (Attribute-based Access Control) technology, this paper proposes an access control scheme, so that users can achieve fine-grained access control of their data when sharing them. The solution uses smart contract to achieve automated and reliable policy evaluation. IPFS (Interplanetary File System) is used for off-chain distributed storage to share the storage pressure of blockchain and guarantee the reliable storage of data. At the same time, all processes in the system are stored in the blockchain, ensuring the accountability of the system. Finally, the experiment proves the feasibility of the proposed scheme.

With the advent of the era of big data, the files that need to be stored in the storage system will increase exponentially. Cloud storage has become the most popular data storage method due to its powerful convenience and storage capacity. However, in order to save costs, some cloud service providers, Malicious deletion of the user's infrequently accessed data causes the user to suffer losses. Aiming at data integrity and privacy issues, a blockchain-based cloud storage integrity verification scheme for recoverable data is proposed. The scheme uses the Merkle tree properties, anonymity, immutability and smart contracts of the blockchain to effectively solve the problems of cloud storage integrity verification and data damage recovery, and has been tested and analyzed that the scheme is safe and effective.

Food supply chain is a complex but necessary food production arrangement needed by the global community to maintain sustainability and food security. For the past few years, entities being a part of the food processing system have usually taken food supply chain for granted, they forget that just one disturbance in the chain can lead to poisoning, scarcity, or increased prices. This continually affects the vulnerable among society, including impoverished individuals and small restaurants/grocers. The food supply chain has been expanded across the globe involving many more entities, making the supply chain longer and more problematic making the traditional logistics pattern unable to match the expectations of customers. Food supply chains involve many challenges like lack of traceability and communication, supply of fraudulent food products and failure in monitoring warehouses. Therefore there is a need for a system that ensures authentic information about the product, a reliable trading mechanism. In this paper, we have proposed a comprehensive solution to make the supply chain consumer centric by using Blockchain. Blockchain technology in the food industry applies in a mindful and holistic manner to verify and certify the quality of food products by presenting authentic information about the products from the initial stages. The problem formulation, simulation and performance analysis are also discussed in this research work.

Identity Management Systems (IdMS) have seemingly evolved in recent years, both in terms of modelling approach and in terms of used technology. The early centralized, later federated and user-centric Identity Management (IdM) was finally replaced by Self-Sovereign Identity (SSI). Solutions based on Distributed Ledger Technology (DLT) appeared, with prominent examples of uPort, Sovrin or ShoCard. In effect, users got more freedom in creation and management of their identities. IdM systems became more distributed, too. However, in the area of interoperability, dynamic and ad-hoc identity management there has been almost no significant progress. Quest for the best IdM system which will be used by all entities and organizations is deemed to fail. The environment of IdM systems is, and in the near future will still be, heterogenous. Therefore a person will have to manage her or his identities in multiple IdM systems. In this article authors argument that future-proof IdM systems should be able to interoperate with each other dynamically, i.e. be able to discover existence of different identities of a person across multiple IdM systems, dynamically build trust relations and be able to translate identity assertions and claims across various IdM domains. Finally, authors introduce identity relationship model and corresponding identity discovery algorithm, propose IdMS-agnostic identity discovery service design and its implementation with use of Ethereum and Smart Contracts.

Smart contracts are an attractive aspect of blockchain technology. A smart contract is a piece of executable code that runs on top of the blockchain and is used to facilitate, execute, and enforce agreements between untrustworthy parties without the need for a third party. This paper offers a review of the literature on smart contract applications in intellectual property management. The goal is to look at technology advancements and smart contract deployment in this area. The theoretical foundation of many papers published in recent years is used as a source of theoretical and implementation research for this purpose. According to the literature review we conducted, smart contracts function automatically, control, or document legally significant events and activities in line with the contract agreement's terms. This is a relatively new technology that is projected to deliver solutions for trust, security, and transparency across a variety of areas. An exploratory strategy was used to perform this literature review.

While it is possible to exchange tokens whose smart contracts are on the same blockchain, cross-exchanging bitcoins for a Bitcoin wrapped token is still cumbersome. In particular, current methods of exchange are still custodial and perform privacy-threatening controls on the users in order to operate. To solve this problem we present BxTB: cross-chain exchanges of bitcoins for any Bitcoin wrapped tokens. BxTB lets users achieve that by bypassing the mint-and-burn paradigm of current wrapped tokens and cross-exchanging already minted tokens in a P2P way. Instead of relaying on HTLCs and the overhead of communication and slowness due to time-locks, we leverage Stateless SPVs, i.e. proof-of-inclusion of transactions in the Bitcoin chain validated through a smart contract deployed on the other blockchain. Furthermore, since this primitive has not been introduced in the academic literature yet, we formally introduce it and we prove its security.

The access control mechanism of most consortium blockchain is implemented through traditional Certificate Authority scheme based on trust chain and centralized key management such as PKI/CA at present. However, the uneven power distribution of CA nodes may cause problems with leakage of certificate keys, illegal issuance of certificates, malicious rejection of certificates issuance, manipulation of issuance logs and metadata, it could compromise the security and dependability of consortium blockchain. Therefore, this paper design and implement a Certificate Authority scheme based on trust ring model that can not only enhance the reliability of consortium blockchain, but also ensure high performance. Combined public key, transformation matrix and elliptic curve cryptography are applied to the scheme to generate and store keys in a cluster of CA nodes dispersedly and securely for consortium nodes. It greatly reduced the possibility of malicious behavior and key leakage. To achieve the immutability of logs and metadata, the scheme also utilized public blockchain and smart contract technology to organize the whole procedure of certificate issuance, the issuance logs and metadata for certificate validation are stored in public blockchain. Experimental results showed that the scheme can surmount the disadvantages of the traditional scheme while maintaining sufficiently good performance, including issuance speed and storage efficiency of certificates.

We propose DecCert, a decentralized public key infrastructure designed as a smart contract that solves the problem of identity attestation on public blockchains. Our system allows an individual to bind an identity to a public blockchain address. Once a claim of identity is made by an individual, other users can choose to verify the attested identity based on the evidence presented by an identity claim maker by staking cryptocurrency in the DecCert smart contract. Increasing levels of trust are naturally built based upon the amount staked and the duration the collateral is staked for. This mechanism replaces the usual utilization of digital signatures in a traditional hierarchical certificate authority model or the web of trust model to form a publicly verifiable decentralized stake of trust model. We also present a novel solution to the certificate revocation problem and implement our solution on the Ethereum blockchain. Further, we show that our design solves Zooko’s triangle as defined for public key infrastructure deployments.

Blockchain smart contracts are prevalent nowadays as numerous applications are developed based on this feature. Though smart contracts are important and widely used, they contain certain vulnerabilities. This paper discusses various security issues that arise in smart contract applications. They are categorized in the smart contract platform, the applications that integrate with the Blockchain, and the vulnerabilities in smart contract code. A detailed study of smart contract-specific vulnerabilities and the defense against those vulnerabilities are presented in this article. Because of certain limitations of platforms or programming language used to write smart contract, there are possibilities of attacks on smart contracts. Hence different security measures or precautions to be taken while writing the smart contract code is discussed in this article. This will prevent the potential attacks happening on Blockchain distributed applications.

Digital identity management system is the securi-ty infrastructure of computer and internet applications. However, currently, most of the digital identity management systems are faced with problems such as the difficulty of cross-domain authentication and interoperation, the lack of credibility of identity authentication, the weakness of the security of identity data. Although the advantages of block-chain technology have attached the attentions of experts and scholars in the field of digital identity management and many digital identity management systems based on block-chain have been built, the systems still can't completely solve the problems mentioned above. Therefore, in this pa-per, an effective digital identity management system model is proposed which combines technologies of self-sovereign identity and oracle with blockchain so as to pave a way in solving the problems mentioned above and constructing a secure and reliable digital identity management system.

This paper deals with how to implement a system that extends insider threat behavior data using private blockchain technology to overcome the limitations of insider threat datasets. Currently, insider threat data is completely undetectable in existing datasets for new methods of insider threat due to the lack of insider threat scenarios and abstracted event behavior. Also, depending on the size of the company, it was difficult to secure a sample of data with the limit of a small number of leaks among many general users in other organizations. In this study, we consider insiders who pose a threat to all businesses as public enemies. In addition, we proposed a system that can use a private blockchain to expand insider threat behavior data between network participants in real-time to ensure reliability and transparency.

With the rapid development of cloud storage technology, an increasing number of enterprises and users choose to store data in the cloud, which can reduce the local overhead and ensure safe storage, sharing, and deletion. In cloud storage, safe data deletion is a critical and challenging problem. This paper proposes an assured data deletion scheme based on multi-authoritative users in the semi-trusted cloud storage scenario (MAU-AD), which aims to realize the secure management of the key without introducing any trusted third party and achieve assured deletion of cloud data. MAU-AD uses access policy graphs to achieve fine-grained access control and data sharing. Besides, the data security is guaranteed by mutual restriction between authoritative users, and the system robustness is improved by multiple authoritative users jointly managing keys. In addition, the traceability of misconduct in the system can be realized by blockchain technology. Through simulation experiments and comparison with related schemes, MAU-AD is proven safe and effective, and it provides a novel application scenario for the assured deletion of cloud storage data.

Social Internet of Vehicle (SIoV) has emerged as one of the most promising applications for vehicle communication, which provides safe and comfortable driving experience. It reduces traffic jams and accidents, thereby saving public resources. However, the wrongly communicated messages would cause serious issues, including life threats. So it is essential to ensure the reliability of the message before acting on considering that. Existing works use cryptographic primitives like threshold authentication and ring signatures, which incurs huge computation and communication overheads, and the ring signature size grew linearly with the threshold value. Our objective is to keep the signature size constant regardless of the threshold value. This work proposes MuSigRDT, a multisignature contract based data transmission protocol using Schnorr digital signature. MuSigRDT provides incentives, to encourage the vehicles to share correct information in real-time and participate honestly in SIoV. MuSigRDT is shown to be secure under Universal Composability (UC) framework. The MuSigRDT contract is deployed on Ethereum's Rinkeby testnet.

Virtual power plants are among the promising ways that variable generation and flexible demand may be optimally balanced in the future. The virtual power plant is an important branch of the energy internet, and it plays an important role in the aggregation of distributed power generation resources and the establishment of virtual power resource transactions. However, in the existing virtual power plant model, the following problems are becoming increasingly prominent, such as safeguard, credit rating system, privacy protection, benefit distribution. Firstly, the operation and transaction mechanism of the virtual power plant was introduced. Then, the blockchain technology is introduced into the virtual power plant transaction to make it more conducive to the information transparent, stable dispatch system, data security, and storage security. Finally, the operation and transaction system based on blockchain technology for the virtual power plant was design.

With the advent of cloud storage services many users tend to store their data in the cloud to save storage cost. However, this has lead to many security concerns, and one of the most important ones is ensuring data integrity. Public verification schemes are able to employ a third party auditor to perform data auditing on behalf of the user. But most public verification schemes are vulnerable to procrastinating auditors who may not perform auditing on time. These schemes do not have fair arbitration also, i.e. they lack a way to punish the malicious Cloud Service Provider (CSP) and compensate user whose data has been corrupted. On the other hand, CSP might be storing redundant data that could increase the storage cost for the CSP and computational cost of data auditing for the user. In this paper, we propose a Blockchain-based public auditing and deduplication scheme with a fair arbitration system against procrastinating auditors. The key idea requires auditors to record each verification using smart contract and store the result into a Blockchain as a transaction. Our scheme can detect and punish the procrastinating auditors and compensate users in the case of any data loss. Additionally, our scheme can detect and delete duplicate data that improve storage utilization and reduce the computational cost of data verification. Experimental evaluation demonstrates that our scheme is provably secure and does not incur overhead compared to the existing public auditing techniques while offering an additional feature of verifying the auditor’s performance.

The term cryptocurrency refers to a digital currency based on cryptographic concepts that have become popular in recent years. Bitcoin is a decentralized cryptocurrency that uses the distributed append-only public database known as blockchain to record every transaction. The incentive-compatible Proof-of-Work (PoW)-centered decentralized consensus procedure, which is upheld by the network's nodes known as miners, is essential to the safety of bitcoin. Interest in Bitcoin appears to be growing as the market continues to rise. Bitcoins and Blockchains have identical fundamental ideas, which are briefly discussed in this paper. Various studies discuss blockchain as a revolutionary innovation that has various applications, spanning from bitcoins to smart contracts, and also about it being a solution to many issues. Furthermore, many papers are reviewed here that not only look at Bitcoin’s fundamental underpinning technologies, such as Mixing and the Bitcoin Wallets but also at the flaws in it.

Data privacy is a key concern for smart contracts handling sensitive data. The existing work zkay addresses this concern by allowing developers without cryptographic expertise to enforce data privacy. However, while zkay avoids fundamental limitations of other private smart contract systems, it cannot express key applications that involve operations on foreign data.We present ZeeStar, a language and compiler allowing non-experts to instantiate private smart contracts and supporting operations on foreign data. The ZeeStar language allows developers to ergonomically specify privacy constraints using zkay’s privacy annotations. The ZeeStar compiler then provably realizes these constraints by combining non-interactive zero-knowledge proofs and additively homomorphic encryption.We implemented ZeeStar for the public blockchain Ethereum. We demonstrated its expressiveness by encoding 12 example contracts, including oblivious transfer and a private payment system like Zether. ZeeStar is practical: it prepares transactions for our contracts in at most 54.7s, at an average cost of 339k gas.

Managing electricity effectively also means knowing as accurately as possible when, where and how electricity is used. Detailed metering and timely allocation of consumption can help identify specific areas where energy consumption is excessive and therefore requires action and optimization. All those interested in the measurement process (distributors, sellers, wholesalers, managers, ultimately customers and new prosumer figures - producers / consumers -) have an interest in monitoring and managing energy flows more efficiently, in real time.Smart meter plays a key role in sending data containing consumer measurements to both the producer and the consumer, thanks to chain 2. It allows you to connect consumption and production, during use and the customer’s identity, allowing billing as Time-of-Use or Real-Time Pricing, and through the new two-way channel, this information is also made available to the consumer / prosumer himself, enabling new services such as awareness of energy consumption at the very moment of energy use.This is made possible by latest generation devices that "talk" with the end user, which use chain 2 and the power line for communication.However, the implementation of smart meters and related digital technologies associated with the smart grid raises various concerns, including, privacy. This paper provides a comparative perspective on privacy policies for residential energy customers, moreover, it will be possible to improve security through the blockchain for the introduction of smart contracts.

We have several issues in most current supply chain management systems. Consumers want to spend money on environmentally friendly products, but they are seldomly informed of the environmental contributions of the suppliers. Meanwhile, each supplier seeks to recover the costs for the environmental contributions to re-invest them into further contributions. Instead, in most current supply chains, the reward for each supplier is not clearly defined and fairly distributed. To address these issues, we propose a supply-chain contribution management platform for fair reward distribution called ‘Advanced Ledger.’ This platform records suppliers' environ-mental contribution trails, receives rewards from consumers in exchange for trail-backed fungible tokens, and fairly distributes the rewards to each supplier based on the contribution trails. In this paper, we overview the architecture of Advanced Ledger and 11 technical features, including decentralized autonomous organization (DAO) based contribution verification, contribution concealment, negative-valued tokens, fair reward distribution, atomic rewarding, and layer-2 rewarding. We then study the requirements and candidates of the smart contract platforms for implementing Advanced Ledger. Finally, we introduce a use case called ‘ESG token’ built on the Advanced Ledger architecture.

As the COVID-19 continues to spread globally, more and more companies are transforming into remote online offices, leading to the expansion of electronic signatures. However, the existing electronic signatures platform has the problem of data-centered management. The system is subject to data loss, tampering, and leakage when an attack from outside or inside occurs. In response to the above problems, this paper designs an electronic signature solution and implements a prototype system based on the consortium blockchain. The solution divides the contract signing process into four states: contract upload, initiation signing, verification signing, and confirm signing. The signing process is mapped with the blockchain-linked data. Users initiate the signature transaction by signing the uploaded contract's hash. The sign state transition is triggered when the transaction is uploaded to the blockchain under the consensus mechanism and the smart contract control, which effectively ensures the integrity of the electronic contract and the non-repudiation of the electronic signature. Finally, the blockchain performance test shows that the system can be applied to the business scenario of contract signing.

In the PKI-CA system with a traditional trust model based on trust chain and centralized private key management, there are some problems with issuing certificates illegally, denying issued certificates, tampering with issuance log, and leaking certificate private key due to the excessive power of a single CA. A novel distributed CA system based on blockchain was constructed to solve the problems. The system applied blockchain and smart contract to coordinate the certificate issuing process, and stored the issuing process logs and information used to verify certificates on the blockchain. It guaranteed the non-tamperability and non-repudiation of logs and information. Aiming at the disadvantage of easy leakage of private keys in centralized management mode, the system used the homomorphism of elliptic encryption algorithm, CPK and transformation matrix to generate and store user private keys safely and distributively. Experimental analysis showed that the system can not only overcome the drawbacks of the traditional PKI-CA system, but also issue certificates quickly and save as much storage as possible to store certificate private keys.

In the traditional Internet of Vehicles, communication data is easily tampered with and easily leaked. In order to improve the trust evaluation mechanism of the Internet of Vehicles and establish a trust relationship between vehicles, a blockchain-based Internet of Vehicles trust evaluation (BBTE) scheme is proposed. First, the scheme uses the roadside unit RSU to calculate the trust value of vehicle nodes and maintain the generation, verification and storage of blocks, so as to realize distributed data storage and ensure that data cannot be tampered with. Secondly, an efficient trust evaluation method is designed. The method integrates four trust decision factors: initial trust, historical experience trust, recommendation trust and RSU observation trust to obtain the overall trust value of vehicle nodes. In addition, in the process of constructing the recommendation trust method, the recommendation trust is divided into three categories according to the interaction between the recommended vehicle node and the communicator, use CRITIC to obtain the optimal weights of three recommended trusts, and use CRITIC to obtain the optimal weights of four trust decision-making factors to obtain the final trust value. Finally, the NS3 simulation platform is used to verify the security and accuracy of the trust evaluation method, and to improve the identification accuracy and detection rate of malicious vehicle nodes. The experimental analysis shows that the scheme can effectively deal with the gray hole attack, slander attack and collusion attack of other vehicle nodes, improve the security of vehicle node communication interaction, and provide technical support for the basic application of Internet of Vehicles security.

The Internet of Vehicles (IoV) has a tremendous prospect for numerous vehicular applications. IoV enables vehicles to transmit data to improve roadway safety and efficiency. Data security is essential for increasing the security and privacy of vehicle and roadway infrastructures in IoV systems. Several researchers proposed numerous solutions to address security and privacy issues in IoV systems. However, these issues are not proper solutions that lack data authentication and verification protocols. In this paper, a blockchain-enabled automated data management system for vehicles has been proposed and demonstrated. This work enables automated data verification and authentication using smart contracts. Certified organizations can only access vehicle data uploaded by the vehicle user to the Interplanetary File System (IPFS) server through that vehicle user’s consent. The proposed system increases the security of vehicles and data. Vehicle privacy is also maintained here by increasing data privacy.