Dependable Public Ledger for Policy Compliance, a Blockchain Based Approach

The ever increasing amount of personal data accumulated by companies offering innovative services through the cloud, Internet of Things devices and, more recently, social robots has started to alert consumers and legislative authorities. In the advent of the first modern laws trying to protect user privacy, such as the European Union General Data Protection Regulation, it is still unclear what are the tools and techniques that the industry should employ to comply with regulations in a transparent and cost effective manner. We propose an architecture for a public blockchain based ledger that can provide strong evidence of policy compliance. To address scalability concerns, we define a new type of off-chain channel that is based on general state channels and offers verification for information external to the blockchain. We also create a model of the business relationships in a smart home setup that includes a social robot and suggest a sticky policy mechanism to monitor cross-boundary policy compliance

Trends in Development of Databases and Blockchain

This work is about the mutual influence between two technologies: Databases and Blockchain. It addresses two questions: 1. How the database technology has influenced the development of blockchain technology?, and 2. How blockchain technology has influenced the introduction of new functionalities in some modern databases? For the first question, we explain how database technology contributes to blockchain technology by unlocking different features such as ACID (Atomicity, Consistency, Isolation, and Durability) transactional consistency, rich queries, real-time analytics, and low latency. We explain how the CAP (Consistency, Availability, Partition tolerance) theorem known for databases influenced the DCS (Decentralization, Consistency, Scalability) theorem for the blockchain systems. By using an analogous relaxation approach as it was used for the proof of the CAP theorem, we postulate a "DCS-satisfiability conjecture." For the second question, we review different databases that are designed specifically for blockchain and provide most of the blockchain functionality like immutability, privacy, censorship resistance, along with database features.Comment: Accepted in The Second International Workshop on Blockchain Applications and Theory (BAT 2020

Trade-offs between Distributed Ledger Technology Characteristics

When developing peer-to-peer applications on distributed ledger technology (DLT), a crucial decision is the selection of a suitable DLT design (e.g., Ethereum), because it is hard to change the underlying DLT design post hoc. To facilitate the selection of suitable DLT designs, we review DLT characteristics and identify trade-offs between them. Furthermore, we assess how DLT designs account for these trade-offs and we develop archetypes for DLT designs that cater to specific requirements of applications on DLT. The main purpose of our article is to introduce scientific and practical audiences to the intricacies of DLT designs and to support development of viable applications on DLT

Bridges Between Islands: Cross-Chain Technology for Distributed Ledger Technology

Since the emergence of blockchain in 2008, today, we see a kaleidoscopic variety of applications built on distributed ledger technology (DLT), including applications for financial services, healthcare, or the Internet of Things. Yet, each application comes with specific requirements for DLT characteristics (e.g., high throughput, scalability). However, trade-offs between DLT characteristics restrict the development of a DLT design (e.g., Ethereum, IOTA) that fits all use cases’ requirements simultaneously. Consequently, separated DLT designs emerged, each specialized to suite dedicated application requirements. To enable the development of more powerful applications on DLT, such DLT islands must be bridged. However, knowledge on cross-chain technology (CCT) is scattered across scientific and practical sources. Therefore, we examine this diverse body of knowledge and provide comprehensive insights into CCT by synthesizing underlying characteristics, evolving patterns, and use cases. Our findings resolve existing contradictions in the literature and provide avenues for future research in an emerging scientific field

Exploring Blockchain Technology through a Modular Lens: A Survey

Blockchain has attracted significant attention in recent years due to its potential to revolutionize various industries by providing trustlessness. To comprehensively examine blockchain systems, this article presents both a macro-level overview on the most popular blockchain systems, and a micro-level analysis on a general blockchain framework and its crucial components. The macro-level exploration provides a big picture on the endeavors made by blockchain professionals over the years to enhance the blockchain performance while the micro-level investigation details the blockchain building blocks for deep technology comprehension. More specifically, this article introduces a general modular blockchain analytic framework that decomposes a blockchain system into interacting modules and then examines the major modules to cover the essential blockchain components of network, consensus, and distributed ledger at the micro-level. The framework as well as the modular analysis jointly build a foundation for designing scalable, flexible, and application-adaptive blockchains that can meet diverse requirements. Additionally, this article explores popular technologies that can be integrated with blockchain to expand functionality and highlights major challenges. Such a study provides critical insights to overcome the obstacles in designing novel blockchain systems and facilitates the further development of blockchain as a digital infrastructure to service new applications

Blockchain's adoption in IoT: The challenges, and a way forward

© 2018 Elsevier Ltd The underlying technology of Bitcoin is blockchain, which was initially designed for financial value transfer only. Nonetheless, due to its decentralized architecture, fault tolerance and cryptographic security benefits such as pseudonymous identities, data integrity and authentication, researchers and security analysts around the world are focusing on the blockchain to resolve security and privacy issues of IoT. However, presently, not much work has been done to assess blockchain's viability for IoT and the associated challenges. Hence, to arrive at intelligible conclusions, this paper carries out a systematic study of the peculiarities of the IoT environment including its security and performance requirements and progression in blockchain technologies. We have identified the gaps by mapping the security and performance benefits inferred by the blockchain technologies and some of the blockchain-based IoT applications against the IoT requirements. We also discovered some practical issues involved in the integration of IoT devices with the blockchain. In the end, we propose a way forward to resolve some of the significant challenges to the blockchain's adoption in IoT