A Blockchain-based Approach for Data Accountability and Provenance Tracking

The recent approval of the General Data Protection Regulation (GDPR) imposes new data protection requirements on data controllers and processors with respect to the processing of European Union (EU) residents' data. These requirements consist of a single set of rules that have binding legal status and should be enforced in all EU member states. In light of these requirements, we propose in this paper the use of a blockchain-based approach to support data accountability and provenance tracking. Our approach relies on the use of publicly auditable contracts deployed in a blockchain that increase the transparency with respect to the access and usage of data. We identify and discuss three different models for our approach with different granularity and scalability requirements where contracts can be used to encode data usage policies and provenance tracking information in a privacy-friendly way. From these three models we designed, implemented, and evaluated a model where contracts are deployed by data subjects for each data controller, and a model where subjects join contracts deployed by data controllers in case they accept the data handling conditions. Our implementations show in practice the feasibility and limitations of contracts for the purposes identified in this paper

SoK: Design, Vulnerabilities and Defense of Cryptocurrency Wallets

The rapid growth of decentralized digital currencies, enabled by blockchain technology, has ushered in a new era of peer-to-peer transactions, revolutionizing the global economy. Cryptocurrency wallets, serving as crucial endpoints for these transactions, have become increasingly prevalent. However, the escalating value and usage of these wallets also expose them to significant security risks and challenges. This research aims to comprehensively explore the security aspects of cryptocurrency wallets. It provides a taxonomy of wallet types, analyzes their design and implementation, identifies common vulnerabilities and attacks, and discusses defense mechanisms and mitigation strategies. The taxonomy covers custodial, non-custodial, hot, and cold wallets, highlighting their unique characteristics and associated security considerations. The security analysis scrutinizes the theoretical and practical aspects of wallet design, while assessing the efficacy of existing security measures and protocols. Notable wallet attacks, such as Binance, Mt. Gox are examined to understand their causes and consequences. Furthermore, the paper surveys defense mechanisms, transaction monitoring, evaluating their effectiveness in mitigating threats

DSMAC: Privacy-Aware Decentralized Self-Management of Data Access Control Based on Blockchain for Health Data

In recent years, the interest in using wireless communication technologies and mobile devices in the healthcare environment has increased. However, despite increased attention to the security of electronic health records, patient privacy is still at risk for data breaches. Thus, it is quite a challenge to involve an access control system especially if the patient’s medical data are accessible by users who have diverse privileges in different situations. Blockchain is a new technology that can be adopted for decentralized access control management issues. Nevertheless, different scalability, security, and privacy challenges affect this technology. To address these issues, we suggest a novel Decentralized Self-Management of data Access Control (DSMAC) system using a blockchain-based Self-Sovereign Identity (SSI) model for privacy-preserving medical data, empowering patients with mechanisms to preserve control over their personal information and allowing them to self-grant access rights to their medical data. DSMAC leverages smart contracts to conduct Role-based Access Control policies and adopts the implementation of decentralized identifiers and verifiable credentials to describe advanced access control techniques for emergency cases. Finally, by evaluating performance and comparing analyses with other schemes, DSMAC can satisfy the privacy requirements of medical systems in terms of privacy, scalability, and sustainability, and offers a new approach for emergency cases