·         Table of Contents (Volume #3, Issue #5)

·         Cover Page (Volume #3, Issue #5)

·         Guest Editors (Volume #3, Issue #5)

·         Editorial (Volume #3, Issue #5)

Paper #1

Dining Philosophers, Byzantine Generals, and the Various Nodes, Users, and Citizens under Blockchain Rule

Denisa Reshef Kera

Abstract: Agreements, consensuses, protocols, resource-sharing, and fairness are all examples of social and political metaphors that define and shape new computational algorithms. The thought experiments and allegories about resource-sharing or agreement between nodes played a vital role in the development of "concurrent programming" (enabling processor power-sharing and process synchronization) and still later in the development of distributed computing (facilitating data access and synchronization). These paved the way for current concepts of consensus mechanisms, smart contracts, and other descriptions of cryptocurrencies, blockchain, distributed ledger, and hashgraph technologies, paradoxically reversing the relations between metaphor and artifact. New computing concepts and algorithmic processes, such as consensus mechanisms, trustless networks, and automated smart contracts or DAOs (Distributed Autonomous Organizations), aim to disrupt social contracts and political decision-making and replace economic, social, and political institutions (e.g., law, money, voting). Rather than something that needs a metaphor, algorithms are becoming the metaphor of good governance. Current fantasies of algorithmic governance exemplify this reversal of the role played by metaphors: they reduce all concepts of governance to automation and curtail opportunities for defining new computing challenges inspired by the original allegories, thought experiments, and metaphors. Especially now, when we are still learning how best to govern the transgressions and excesses of emerging distributed ledger technologies, productive relations between software and allegory, algorithms and metaphors, code and law are possible so long as they remain transitive. Against this tyranny of algorithms and technologies as metaphors and aspirational models of governance, we propose sandboxes and environments that allow stakeholders to combine prototyping with deliberation, algorithms with metaphors, codes with regulations.

Keywords: Blockchain; Bitcoin; Metaphors; Thought Experiments; Algorithms; Governance; Automation.

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Paper #2

A Survey on Efficient Parallelization of Blockchain-based Smart Contracts

Alessio Meneghetti, Tommaso Parise, Massimiliano Sala and Daniele Taufer

Abstract: The main problem faced by smart contract platforms is the amount of time and computational power required to reach consensus. In a classical blockchain model, each operation is in fact performed by each node, both to update the status and to validate the results of the calculations performed by others. In this short survey we sketch some state-of-the-art approaches to obtain an efficient and scalable computation of smart contracts. Particular emphasis is given to sharding, a promising method that allows parallelization and therefore a more efficient management of the computational resources of the network.

Keywords: Blockchain; Bitcoin; Metaphors; Thought Experiments; Algorithms; Governance; Automation.

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Paper #3

Blockchain Technology in IoT Systems: Review of the Challenges

Yeray Mezquita, Roberto Casado, Alfonso Gonzalez-Briones, Javier Prieto and Juan Manuel Corchado

Abstract: Internet of Things (IoT) platforms have a great number of vulnerabilities which cyber-attackers can exploit. A possible solution largely contemplated in the state of the art is to make use of blockchain technology in any IoT system to enhance the security of the platform while improving other of its aspects. Although there are valuable benefits of the use of IoT platforms based on blockchain technology, it is worth studying the different alternatives between blockchain technologies, because all of them have their own limitations that are not suitable for every use case scenario. In this work, we listed a number of flaws that blockchain technology has in this respect. We have identified that, most of the flaws can be overcome by adapting the variants of this technology to the specific needs of the IoT platform. Every IoT system based on blockchain technology, should perform a systematic analysis of their needs, identifying what are the blockchain features sought for that scenario, to choose the solution that best meets the needs among the different blockchain technology alternatives.

Keywords: Blockchain; IoT; Security; Review.

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Paper #4

Two-tier Blockchain Timestamped Notarization with Incremental Security

Alessio Meneghetti, Armanda O. Quintavalle, Massimiliano Sala and Alessandro Tomasi

Abstract: Digital notarization is one of the most promising services offered by modern blockchain-based solutions. We present a digital notary design with incremental security and cost reduced with respect to current solutions. A client of the service receives evidence in three steps. In the first step, evidence is received almost immediately, but a lot of trust is required. In the second step, less trust is required, but evidence is received seconds later. Finally, in the third step evidence is received within minutes via a public blockchain.

Keywords: Blockchain (BC); Notarization; Provable security; Cryptography.

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Paper #5

Privacy Laws in the Blockchain Environment

Rocio de la Cruz

Abstract: The compatibility between emerging technology such as Blockchain and the new data protection obligations has been a matter of discussion since the European General Data Protection Regulation (“GDPR”) came into force back in 2018. The main reason is that GDPR is considered the Regulation that has incorporated the strongest obligations and enforcement consequences. There are some areas of tension on how to comply with these obligations, some of which are still a matter of discussion that have not been concluded by regulators or in court. In this chapter, I set out an overview of the main obligations, relevant areas of tension and set out an opinion on what I have seen that in practice is working the best, and how I recommend dealing with these issues in practice, in order to do an assessment applied to a particular context in which a Blockchain network is used.

Keywords: Blockchain; Privacy; Data Protection Laws; General Data Protection Regulation (GDPR); Data Protection.

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