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This paper looks at current projects in the field of Blockchain in education, their specific areas of application, possible advantages and weaknesses. Three examples developed by the team of authors are introduced in detail. First: Gallery-Defender a Serious Game, which was adapted to serve as a demonstrator in a stand-alone version to show the possibility to carry out exams directly from within the game and store the grades and meta-data on Blockchain. Second: Art-Quiz, an e-learning tool, which can be integrated into existing LMS systems and map exam results and further data using Blockchain technologies. Both were developed following an iterative design process. And third: The results of a focus group, which simulated the assignment of grades after an oral online exam. The three examples presented here are based on the Blockchain system Ardor/Childchain Ignis, but each demonstrator has a different set of features and approaches.
In addition, the integration of various Blockchain solutions was conceptually designed to make a Multi-Chain model possible.
With the increasing usage of blockchain technology, legal challenges such as GDPR compliance arise. Especially the right of erasure is considered challenging as blockchains are tamperproof by design. Several approaches investigated
possibilities to weaken the tamperproof aspect of blockchains in favor of GDPR compliance. This paper presents several approaches, then focuses on chameleon hash functions by evaluating the possibility to use these specific functions in a private blockchain. The goal of the built system is to take a step towards the digitization of the bill of lading used in international trade. This paper describes the developed software as well as the core considerations around the system such as network design or block structure.
Both cryptocurrency researchers and early adopters of cryptocurrencies agree that they possess a special kind of materiality, based on the laborious productive process of digital ‘mining’ [1]. This idea first appears in the Bitcoin White Paper [2] that encourages Bitcoin adopters to construct and justify its value in metaphoric comparison to gold mining. In
this paper, I explore three material aspects of blockchain: physical infrastructure, human language and computer code. I apply the concept of 'continuous materiality' [3] to show how these three aspects interact in practical implementations of blockchain such as Bitcoin and Ethereum. I start from the concept of ‘digital metallism’ that stands for ‘fundamental value’ of cryptocurrencies, and end with the move of Ethereum to ‘proof-of-stake’, partially as a countermeasure against ‘evil miners’. I conclude that ignoring material aspects of blockchain technology can only further problematize complicated relations between their technical, semiotic and social materiality.
After creating a new blockchain transaction, the next step usually is to make miners aware of it by having it propagated through the blockchain’s peer-to-peer network. We study an unintended alternative to peer-to-peer propagation: Exclusive mining. Exclusive mining is a type of collusion between a transaction initiator and a single miner (or mining pool). The initiator sends transactions through a private channel directly to the miner instead of propagating them through the peerto-peer network. Other blockchain users only become aware of these transactions once they have been included in a block by the miner. We identify three possible motivations for engaging in exclusive mining: (i) reducing transaction cost volatility (“confirmation as a service”), (ii) hiding unconfirmed transactions from the network to prevent frontrunning and (iii) camouflaging wealth transfers as transaction costs to evade taxes or launder money. We further outline why exclusive mining is difficult to prevent and introduce metrics which can be used to identify mining pools engaging in exclusive mining activity.
The set of transactions that occurs on the public ledger of an Ethereum network in a specific time frame can be represented as a directed graph, with vertices representing addresses and an edge indicating the interaction between two addresses.
While there exists preliminary research on analyzing an Ethereum network by the means of graph analysis, most existing work is focused on either the public Ethereum Mainnet or on analyzing the different semantic transaction layers using
static graph analysis in order to carve out the different network properties (such as interconnectivity, degrees of centrality, etc.) needed to characterize a blockchain network. By analyzing the consortium-run bloxberg Proof-of-Authority (PoA) Ethereum network, we show that we can identify suspicious and potentially malicious behaviour of network participants by employing statistical graph analysis. We thereby show that it is possible to identify the potentially malicious
exploitation of an unmetered and weakly secured blockchain network resource. In addition, we show that Temporal Network Analysis is a promising technique to identify the occurrence of anomalies in a PoA Ethereum network.
Decentralizing Smart Energy Markets - tamper-proof-documentation of flexibility market processes
(2020)
The evolving granularity and structural decentralization of the energy system leads to a need for new tools for the efficient operation of electricity grids. Local Flexibility Markets (or "Smart Markets") provide platform concepts for market based congestion management. In this context there is a distinct need for a secure, reliable and tamper-resistant market design which requires transparent and independent monitoring of platform operation. Within the following paper different concepts for blockchain-based documentation of relevant processes on the proposed market platform are described. On this basis potential technical realizations are discussed. Finally, the implementation of one setup using Merkle tree operations is presented by using open source libraries.
Procurement processes are deemed to lack supporting digital technologies that raise efficiency and automation.
Blockchain solutions are piloted in procurement in order to offer a decentralized IT infrastructure covering these needs. This paper aims at identifying current blockchain approaches in the field of procurement and presenting affected business processes. In order to get an overview of the current state of the art, a systematic literature mapping is conducted.
Moreover, the out-comes are gathered and categorized in a classification scheme. Based on the analysis, systematic maps are presented to showcase relevant findings. Within the findings, several blockchain use cases in the field of procurement are identified and information about addressed challenges, utilized blockchain frameworks and affected business processes are extracted.
The financial world of blockchains is mostly covered by Bitcoin, taking up about 210 billion dollars in market cap. Despite the huge security and independence which the technology offers to the users, it's not quite easy to adapt with upcoming applications due to the regulated infrastructure behind. For small-scale transactions, everyday use applications or the access to a variety of crypto technologies and projects, Bitcoin is relatively limited in future development. The compatibility for most of those applications is covering currencies from more development-driven blockchains like Ethereum. Those want to reach out for the user base that's already in hold of Bitcoins and offer them a seamless transition to new applications without the risk of losing their funds. Within the article, atomic swaps and tokenization are covered up and current approaches compared. Both mechanisms are used to fulfill this symbiosis between Bitcoin and Ethereum.
To get a more practical view, an example on how to implement such a tokenization within an app is shown. This will give deeper insights and offers inspiration for digital identity-based app development.
To enable smart devices of the internet of things to be connected to a blockchain, a blockchain client needs to run on this hardware. With the Trustless Incentivized Remote Node Network, in short Incubed, it will be possible to establish a decentralized and secure network of remote nodes, which enables trustworthy and fast access to a blockchain for a large number of low-performance IoT devices. Currently, Incubed supports the verification of Ethereum data. To serve a wider audience and more applications this paper proposes the verification of Bitcoin data as well, which can be achieved due to the modularity of Incubed. This paper describes the proof data that is necessary for a client to prove the correctness of a node’s response and the process to verify the response by using this proof data as well. A proof-object which contains the proof data will be part of every response in addition to the actual result. We design, implement and evaluate Bitcoin verification for Incubed. Creation of the proof data for supported methods (on the server-side) and the verification process using this proof data (on the client-side) has been demonstrated. This enables the verification of Bitcoin in Incubed.
Mathematics behind the Zcash
(2020)
Among all the new developed cryptocurrencies, Zcash comes out to be the strongest cryptocurrency providing both transparency and anonymity to the transactions and its users by deploying the strong mathematics of zk-SNARKs. We discussed the zero knowledge proofs as a building block for providing the functionality to zk-SNARKs. It offers schnorr protocol which is further used in Zcash transactions where the validation of sent transaction is proved by cryptographic proof. Further, we deploy zk-SNARKs following common reference string that allows sender to prove that she knows a secret such that the proof is succinct, can be verified and does not leak the secret. Non-malleability, small proofs and effective verification make zk-SNARKs a classic tool in Zcash. We deal with NP problems therefore we have considered the elliptic curve cryptography to provide the security. Lastly, we explain Zcash transaction, the corresponding transaction completely hides the sender, receiver and amount of transaction using zero knowledge proof.