Blockchain Papers

Francois Crafford

No abstract is available for this record.

Yves Christian Elloh Adja, Badis Hammi, Ahmed Serhrouchni, Sherali Zeadally

No abstract is available for this record.

Mengjie Chen, Yi Xiao, Daoyuan Wu, Jianliang Xu · 6 authors

The popularity of smartphones has led to the growth of mobile app markets, creating a need for enhanced transparency, global access, and secure downloading. This paper introduces AGChain, a blockchain-based gateway that enables trustworthy app delegation within existing markets. AGChain ensures that markets can continue providing services while users benefit from permanent, distributed, and secure app delegation. During its development, we address two key challenges: significantly reducing smart contract gas costs and enabling fully distributed IPFS-based file storage. Additionally, we tackle three system issues related to security and sustainability. We have implemented a prototype of AGChain on Ethereum and Polygon blockchains, achieving effective security and decentralization with a minimal gas cost of around 0.002 USD per app upload (no cost for app download). The system also exhibits reasonable performance with an average overhead of 12%.

Ningyuan Chen, David Siu-Yeung Cho

Online social networks (OSN) are becoming more important in people's daily life, however, all popular OSNs are centralized, and this raises a series of security, privacy and management issues. A decentralized architecture based on blockchain technology provides the ability to solve above issues. In this paper, an OSN service is developed based on blockchain technology in order to make it operate decentralized. Large volume of data normally required low-security requirements can be stored in Interplanetary Filesystem (IPFS) to make data decentralized. A decentralized autonomous organization is developed for user autonomy, users can self-manage the OSN in a democratic way.

Wei Zhou

Decentralized application (DAPP), replacing traditional business logic and data access layer with block chain, is a new form of Internet service. Testing DAPP requires large-scale distributed systems. Performing experiments in a real system is costly and difficult. This article carefully analyses the process of block generation and synchronization and explains the reasons for the low efficiency of block chain system simulation. We incorporate fuzzy rule based model for enhancing the logging system in blockchain. Rules based on fuzzy are utilized inside system of fuzzy logic to obtain outcome on basis of input variables. The data of Ethereum and Bitcoin proves that the block generation interval conforms to the exponential distribution, and the real PoW calculation can be replaced with random numbers. Both block verification and network propagation processes have latency, which can be simulated with asynchronous messaging. Based on the above analysis, this article proposes a high-performance simulation method based on event-driven model, which is suitable for describing the communication and synchronization behave our of block chain networks. The method can effectively describe the block generation, the synchronization process between nodes, and supports different equity proof forms. Using this method, the performance of the PoW systemis tested. Under the ecs.c6.xlargeinstance,the simulation running speed reaches 782 times of actual system. Further experiments show that this method can be efficiently used in larger-scale networks and is an effective tool for DAPP developing and testing.

Muhammad Anas Imtiaz, David Starobinski, Ari Trachtenberg, Nabeel Younis

Efficient and reliable propagation of blocks is vital to the scalability of the Bitcoin network. As a result, several schemes, such as the compact block protocol (BIP 152), have been proposed over the last few years to speed up the block propagation. Even so, we provide experimental evidence that (i) the vast majority (97%) of Bitcoin nodes exhibit only intermittent network connectivity (i.e., churn), and (ii) this churn results in significant number of unsuccessful compact blocks, roughly three times the statistic for continuously connected nodes. We conduct experiments on the Bitcoin network that show that churn results in a roughly five fold increase in block propagation time (i.e., 566.89 ms vs. 109.31 ms) on average. To effect our analysis, we develop a statistical model for churn, based on empirical network data, and use this model to actuate live test nodes on the Bitcoin network. The performance of the system is measured within a novel framework that we developed for logging the internal behavior of a Bitcoin node, and which we share for public use. Finally, to mitigate the problem of missing transactions in churning nodes, we propose and implement into Bitcoin Core a new synchronization protocol, dubbed MempoolSync. Our measurements show that churning nodes implementing MempoolSync experience significantly better performance than standard nodes not implementing MempoolSync, including average block propagation delay reduced by over 50%.

Avi Mizrahi, Noam Koren, Ori Rottenstreich

Merkle trees play a crucial role in blockchain networks in organizing network state. They allow proving a particular value of an entry in the state to a node that maintains only the root of the Merkle trees, a hash-based signature computed over the data in a hierarchical manner. Verification of particular state entries is crucial in reaching a consensus on the execution of a block where state information is required in the processing of its transactions. For instance, a payment transaction should be based on the balance of the involved accounts. The proof length affects the network communication and is typically logarithmic in the state size. In this paper, we take advantage of typical transaction characteristics for better organizing Merkle trees to improve blockchain network performance. We focus on the common transaction processing where Merkle proofs are jointly provided for multiple accounts. We provide lower bounds for the communication cost and describe algorithms based on traffic patterns can significantly reduce them. We rely on real blockchain data to show the savings allowed by our approach.

Vu Trung Duong Le, Ramin Moazeni, Melody Moh

No abstract is available for this record.

Bozhi Wang, Shiping Chen, Lina Yao, Qin Wang

No abstract is available for this record.

Anna S. Shaleva, Vladimir Korkhov

No abstract is available for this record.

Takaaki Yanagihara, Akihiro Fujihara

No abstract is available for this record.

Runchao Han, Jiangshan Yu, Haoyu Lin, Shiping Chen · 5 authors

No abstract is available for this record.

Kostas Messanakis, Petros Demetrakopoulos, Yannis Kotidis

No abstract is available for this record.

Mitsuyoshi Imamura, Kazumasa Omote

No abstract is available for this record.

Sara Ghaemi

The distributed ledger technology (DLT) has been envisioned to be a disruptive technology with applications in various industries. For the DLTs to be effectively used in practice, it is crucial to assess their performance in different use cases and scenarios. In this thesis, we first conduct a systematic survey on the performance evaluation of distributed ledgers. Then we identify and present the performance evaluation techniques, the most important performance metrics, and the bottlenecks of various well-known DLTs. Finally, we present a list of possible directions for future research. Our survey identifies the lack of a detailed performance evaluation for DAG-based distributed ledgers presented so far. Compared to blockchains, DAG-based DLTs offer better performance and scalability by design. In the second part of this thesis, we focus on the performance evaluation of IOTA, which is the prominent implementation of DAG-based distributed ledgers. In this work, we investigate the impact of different design parameters on the performance of an IOTA network. We then propose a layered model to help the users determine the optimal waiting time to resend an unconfirmed transaction. The results can be used by both system designers and users to support their decision making. In the third part of this thesis, we use the findings from the previous two parts to design an open blockchain-based serverless computing platform called ChainFaaS that runs on personal computers. To better understand the capacity of personal computers, we conducted a survey that aims to find their unused computational power. The results indicate that the typical CPU utilization of a personal computer is only 24.5% and, on average, a personal computer is only used 4.5 hours per day. This shows a significant computational potential that can be used towards distributed computing. In this work, we introduce ChainFaaS with the motivation to use the computational capacity of personal computers as well as to improve developers' experience of internet-based computing services by reducing their costs, enabling transparency, and providing reliability. We propose the design of ChainFaaS and then implement and evaluate a prototype of this platform to show the feasibility of this paradigm. The current implementation of ChainFaaS provides payment using a monetary smart contract on the blockchain network. For this platform to be used in practice, ChainFaaS needs to support payment in established cryptocurrencies. As a result, the blockchain network in ChainFaaS needs to interoperate with other distributed ledger technologies to enable such payments. In the last part of this thesis, we investigate a possible solution to enable interoperability in blockchains. We propose a blockchain interoperability solution for permissioned blockchains based on the publish/subscribe architecture. We then implement a prototype of the proposed solution and evaluate its performance. The result of this research not only enables ChainFaaS to support payments in established cryptocurrencies, but it also allows any other blockchain-based application to interoperate with other blockchain networks and use the data and information available on them.

Dimitri Samorukov

Dezentrale Anwendungen werden, im Gegensatz zu zentralisierten Ansätzen, durch eine Unterstützergemeinschaft betrieben. Diese unterliegen keiner zentralen, kontrollierenden, eventuell sogar bösartigen Instanz. Viele Anwendungsgebiete werden durch dezentrale Ansätze abgedeckt. Beispiele hierfür sind dezentrale soziale Netzwerke, Währungen, Logbücher (engl. distributed ledger, i.e. blockchain). Durch eine breite Unterstützung sind die dezentralen Ansätze in der Lage, die marktbeherrschende Stellung einiger weniger Anbieter aufzubrechen und eine echte neutrale, offene Alternative anzubieten. Betrachtet man die Komponenten einer dezentralen Anwendung so trifft man auf der untersten Ebene auf die Hardwareebene, einzelne Peers die durch ein Netzwerk miteinander kommunizieren können und durch einen Operator verwaltet werden. Auf der höheren Anwendungsebene trifft man auf Benutzer, die auf die Dienste der Anwendung mit Hilfe von Operationen zugreifen und auf Daten der Anwendung, sogn. Verwaltungsstruktur. Die Hardwareebene stellt Ressourcen bereit, die durch die Anwendungsebene konsumiert werden. Leider leidet die Akzeptanz der dezentralen Anwendungen an Performanz der Operationen. Die Ursachen hierfür liegt in den unzureichenden Ressourcen der Hardware-Ebene oder ungünstiger Platzierung der Verwaltungsstruktur bezüglich ausgeführter Operationen. Die Ursache der unzureichenden Ressourcen in der Hardware-Ebene liegt u. A. an der absichtlichen Abwanderung der einzelnen Peers, aufgrund der dauerhaften Überlastung. In dieser Arbeit wird gezeigt, dass die günstige Platzierung der Verwaltungsstruktur bei gleichzeitig strikter Einhaltung der durch den Operator bereitgestellten Ressourcen dazu genutzt werden kann die Performanz der Operationen zu erhöhen. Damit werden die Bedürfnisse der Operatoren und Benutzer berücksichtigt, was auch zur verbesserten Akzeptanz der dezentralen Ansätze führt. Die Ergebnisse der gewählten Lösung zeigen, dass wenn ein einzelner Peer die ihm bekannten Teile der Verwaltungsstruktur optimal innerhalb seiner Nachbarschaft verschiebt, dies die Ausführungszeiten der Operationen reduziert. Somit wird ihre Performance deutlich verbessert.

Juan A. Garay, Yu Shen

No abstract is available for this record.

Shinichi Miyazawa

No abstract is available for this record.

Foysal Miah, Samuel Onalo, Eckhard Pflüegel

No abstract is available for this record.

Julien Hatin, E. Bertin, Baptiste Hemery, Nour El Madhoun

Blockchain technology has gained increasing attention from research and industry over the recent years. This interest is mainly due to its core property that allows users to perform transactions without a Trusted Third Party (TTP), while offering a transparent and fully protected tracking of these transactions. However, there is a lack of reference models to describe and compare various Blockchain technologies, leading to some confusion between different kinds of solutions. We propose in this paper a reference model aiming to assess and compare different kind of Blockchain-based ecosystems, including Decentralized Applications (DApp).

Aman Bhargava, Kartik Shankhavaram, Priyanshu Agarwal, Jayaprakash Kar

No abstract is available for this record.

Zlate Dodevski, Sonja Filiposka, Anastas Mishev, Vladimir Trajkovik

Sensitivity of the health-related data and the focus on compliance and security has traditionally emphasized the need for centralized approach while implementing Electronic Health Records (EHR) systems. These one-institutional architectural designs are leading to fragmented and scattered pieces of valuable data across various data warehouses and silos. Interoperability challenges arise due to the absence of unified data management and exchange mechanisms making the social need for fundamental design changes bigger. The capability of a distributed ledger technology and blockchain to offer immutable, decentralized and cryptographically secured record of transactions throughout a peer-to-peer network can facilitate better collaboration and increased interoperability in the field of health and insurance information exchange processes. The paper examines different approaches and application of blockchain technology and identifies which implementations of components are more suitable and beneficial for the specific eco-system analyzed in the paper. This paper presents alternative way of dealing with information exchange across multiple stakeholders by justifying the use of decentralized approach, distributed access and solution how to comprehensively track and assemble health related data. We propose an architectural design and overview of a specific use case with focus on information exchange processes between health insurance providers and health care organizations, by using blockchain as an underlying technology. The architectural overview and data flows, backed up by sequence diagrams from specific use cases offered in this paper, can serve as a guide to the blockchain technology adoption and initial setup.

Gerald R. Gray

No abstract is available for this record.

Hyunsu Mun, Soohyun Kim, Youngseok Lee

No abstract is available for this record.