Blockchain-empowered federated learning based solutions for Internet of Things security, privacy, and performance

The Internet of Things (IoT) is a rapidly growing technology that connects millions of devices together. However, as more devices connect, the importance of ensuring security, privacy, and performance becomes paramount. Training performance is affected without proper protocols in place, and devices can get compromised. This research focuses on...

An evaluation of the reentrancy vulnerability on GoQuorum-based smartcontracts

Within the context of the Ethereum blockchain protocol, reentrancy is a well-known and well-researched smart contract vulnerability. However, when considering GoQuorum, an Ethereum soft fork, barely any research discussing smart contract vulnerabilities exists. This report aims to partly fill this research gap by evaluating the reentrancy smart...

Revisiting smart contract vulnerabilities in Hyperledger Fabric

Hyperledger Fabric is a permissioned enterprise blockchain allowing organizations to collaborate and automate processes via smart contracts. However, these contracts could contain security vulnerabilities leading to unexpected behavior or other negative consequences. Therefore, this study takes a closer look at three reported smart contract...

Investigating Arbitrageurs and Oracle Manipulators in Ethereum

Smart contracts on Ethereum enable billions of dollars of value to be transacted in a decentralised, transparent and trustless environment. However, adversaries lie await in the Dark Forest, waiting to exploit any and all smart contract vulnerabilities in order to extract profits from unsuspecting victims in this new financial system. As the...

A Universal Framework for Claim Portability in Self-Sovereign Identity Applications

Self-sovereign identity (SSI) provides users of the internet control over their own data by letting them store it on their own device or in a decentralized way, such as on a blockchain. The Super App is an SSI application currently under development by the Delft Blockchain Lab, but it still lacks one of the core features of SSI, which is...

Privacy Preservation in a Blockchain-Based Healthcare System

The continuous generation of a large volume of health data from different sources has led to healthcare being a data-intensive domain. To achieve innovative advances in medical treatment procedures and to provide personalized healthcare services to the patients this data needs to be shared among different medical facilities. However, because...

An Evaluation of Privacy Protection in Blockchain-Based Self-Sovereign Identity

Digital identity management has been established in a mainly centralized manner. In response to a lack of control in current identity management systems, the concept of Self-Sovereign Identity (SSI) was defined to enable decentralization. Recently, this concept gained traction, and several implementations have been proposed. The decentralized...

LRFP : Extending local routing protocols in layer 2 networks with a secure fee model

Blockchains like Bitcoin are known to be victim of scalability issues. The lack in high throughput and low latency form a great bottleneck to its network. A promis- ing solution are layer 2 protocols, more precisely payment channel networks (PCN). Payment success rates are a common metric in these networks. These rates can be in- creased by...

Comparing Lightning Routing Protocols to Routing Protocols with Splitting

The largest payment channel network, Bitcoin Lightning, shows a potential alternative to cur- rent financial systems, overcoming the scalability limitations of blockchain. Source onion routing is used to route payments, but novel routing protocols claim improved effectiveness by employ- ing strategies not compatible with the current state of...

Privacy-Preserving Techniques in Blockchain-Based Food Supply Chain

The following paper aims to investigate what and how are the main privacy-preserving methods applied in the blockchain-based supply chain industry scenario, with a primary focus on the food sector. Recent developments, such as the exordium of cryptocurrencies to increment efficiency, are withal addressed. Overviews of key use cases in industry...

Integrating Consent Management Techniques into Blockchain-Based Medical Data Sharing

The health industry is a data-intensive domain. Sharing medical data between medical facilities is necessary for providing good healthcare as well as for research in the healthcare domain. However, due to the sensitive and personal nature of health data, challenges arise when sharing this data. Consent management is a key aspect. The use of...

Security and privacy in medical data sharing through blockchain

The sharing of medical data is becoming ever more important. More and more health-related data is being generated everyday and as will be shown later, its primary as well as its secondary usage brings many benefits to the healthcare system. However, medical data systems are not fail proof and are often the target of cyber-attacks, compromising...

Improving the Anonymity of Layer-Two Blockchains Adding Random Hops

The Bitcoin Lightning Network is a layer-two solution that promises instant payments, scalability, and low transaction fees on top of the Bitcoin blockchain. In case there is no direct channel between the sender and receiver, the routing algorithm uses source routing and a shortest path algorithm to determine the hops in a transaction. However,...

Grip on Energy: with Blockchain Technology

Switching energy suppliers can be a time consuming process and the manner in which permissions regarding consumer data are stored lacks transparency. To overcome these issues, a solution was proposed in the form of a mandate register. Said register keeps track of which consumer gave what permission, regarding energy data, to whom. In this...

Indisputable GDPR compliant signatures in ContractChain

Nowadays, entering into a contract with an overseas company still relies on postal services to send a printed contract, which is signed on paper. Lizard Global is developing an online platform for constructing, reviewing and signing digital contracts for one of their clients. In the original system, when a signee signed a contract, his personal...

Digital Voting Pass: One step towards the digitalization of the entire voting process

The Dutch electoral voting system is designed in a way that does not fit in the current era of the digital transformation. Almost every procedure during the elections is done manually and change in policy is very difficult as it requires a change in legislation.<br/>This thesis explores a more trustworthy, transparent and less expensive way of...