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2,350 results · page 77 of 98
Feng Shen, Long Yu, Zhen Liu, Zhiqiang Liu · 7 authors
No abstract is available for this record.
Santiago Palladino
In the previous chapter, we addressed user onboarding challenges, one of the two main issues for Ethereum mass adoption. The second of them, which we will tackle in this chapter, is scalability. The Ethereum network, as it is today, can handle about 15 transactions per second – this throughput must be shared among all Ethereum applications globally. This has led to single applications cluttering the entire network due to a spike in their usage to the point of rendering all dapps unusable for brief periods. In this chapter, we will introduce state channels and sidechains, two of the most widely used scalability solutions.
Yackolley Amoussou-Guenou, Antonella Del Pozzo, Maria Potop-Butucaru, Sara Tucci-Pergiovanni
Committee-based blockchains are among the most popular alternatives of proof-of-work based blockchains, such as Bitcoin. They provide strong consistency (no fork) under classical assumptions, and avoid using energy-consuming mechanisms to add new blocks in the blockchain. For each block, these blockchains use a committee that executes Byzantine-fault tolerant distributed consensus to decide the next block they will add in the blockchain. Unlike Bitcoin, where there is only one creator per block, in committee-based blockchain any block is cooperatively created. In order to incentivize committee members to participate in the creation of new blocks, rewarding schemes have to be designed. In this paper, we study the fairness of rewarding in committee-based blockchains and we provide necessary and sufficient conditions on the system communication under which it is possible to have a fair reward mechanism.
Alexei Zamyatin, Nicholas Stifter, Aljosha Judmayer, Philipp Schindler · 6 authors
No abstract is available for this record.
Stefano Bistarelli, Claudio Pannacci, Francesco Santini
No abstract is available for this record.
Sheng He, Yishuang Ning, Huan Chen, Chunxiao Xing · 5 authors
No abstract is available for this record.
Luis Cintron, Scott Graham, Douglas D. Hodson, Barry Mullins
No abstract is available for this record.
Gengrui Zhang, Chengzhong Xu
No abstract is available for this record.
Rok Meden, Anton Kos
No abstract is available for this record.
Tong Zhou, Xiaofeng Li, He Zhao
In today's digital information age, the conflict between the public's growing awareness of their own data protection and the data owners' inability to obtain data ownership has become increasingly prominent. The emergence of blockchain provides a new direction for data protection and data tokenization. Nonetheless, existing cryptocurrencies such as Bitcoin using Proof-of-Work are particularly energy intensive. On the other hand, classical protocols such as Byzantine agreement do not work efficiently in an open environment. Therefore, in this paper, we propose a permission-less blockchain with a novel double-DAG (directed acyclic graph) architecture called DLattice, where each account has its own Account-DAG and all accounts make up a greater Node-DAG structure. DLattice parallelizes the growth of each account's Account-DAG, each of which is not influenced by other accounts' irrelevant transactions. DLattice uses a new DPoS-BA-DAG(PANDA) protocol to reach consensus among users only when the forks are observed. Based on proposed DLattice, we introduce a process of data tokenization, including data assembling, data anchoring, and data authorization. We implement DLattice and evaluate its performance on 25 ECS virtual machines, simulating up to 500 nodes. The experimental results show that DLattice reaches a consensus in 10 seconds, achieves desired throughput, and incurs almost no penalty for scaling to more users.
Benedikt Kirpes, Micha Roon, Christopher Burgahn
The mobility sector experiences a fundamental shift to more connected, autonomous, shared and electric means of transportation. For an electric mobility system to function, an efficient and reliable electric vehicle charging network is required. The Open Charging Network, which is built and curated by the Share&Charge Foundation is a digital, open and decentralized infrastructure for operating and connecting assets of the e-mobility ecosystem like charge points and electric vehicles. In such a network validity and consistency of data are crucial. Since the underlying information system is designed based on distributed ledger technologies and distributed hash tables, also the validation of data for the respective key-value store should be implemented and executed in a distributed manner. In this paper, we contribute to the body of research by analyzing the current situation in distributed systems and presenting the design and development of a mechanism for a distributed data validation. We provide an outlook into the future implementation within the Open Charging Network, where the solution will be demonstrated in a suitable context. Further it will be evaluated regarding the primary requirement of data validity and secondary requirements such as availability, reliability and scalability.
Meg Murray
Blockchain technology, which supports the bitcoin cryptocurrency, has risen to prominence as the technology that will transform how business transactions occur and parties manage assets over the Internet. A decentralized system, the blockchain provides a way to digitally record and securely store verifiable and immutable transactions, which eliminates the need for trusted third-party intermediaries. While simplistically described as a decentralized ledger, the blockchain is a complex technology that integrates peer-to-peer networking, cryptography, and distributed consensus. In this paper, I explain blockchain’s components, describe how a blockchain works, identify use case examples from various industries, explore potentials and limitations, and speculate on the progressive adoption of the blockchain as a transformative technology.
Pablo G. Bringas, Iker Pastor, Giuseppe Psaila
No abstract is available for this record.
Emil Saweros, Yeong-Tae Song
No abstract is available for this record.
Massimo Bartoletti, Letterio Galletta, Maurizio Murgia
The Ethereum platform supports the decentralized execution of smart contracts, i.e. computer programs that transfer digital assets between users. The most common language used to develop these contracts is Solidity, a Javascript-like language which compiles into EVM bytecode, the language actually executed by Ethereum nodes. While much research has addressed the formalisation of the semantics of EVM bytecode, relatively little attention has been devoted to that of Solidity. In this paper we propose a minimal calculus for Solidity contracts, which extends an imperative core with a single primitive to transfer currency and invoke contract procedures. We build upon this formalisation to give semantics to the Ethereum blockchain. We show our calculus expressive enough to reason about some typical quirks of Solidity, like e.g. re-entrancy.
Karl Wüst, Siniša Matetić, Moritz Schneider, Ian Miers · 6 authors
No abstract is available for this record.
Luong, Dang Hai
Centralized network solution have been around for a long time, despite having a considerable issue of trust, in which users need to rely on the implementation of the system. During unfortunate incidents such as centralized server hacking attacks, users' data can be stolen and distorted, as well as not available while requested. Blockchain is discovered and believed to be a distributed network solution which can mitigate the above issue. \n \nThis bachelor's thesis studies how blockchain network can be integrated into a social financial mobile application. The research is completed by developing a smart contract and connect it with the mobile application. The smart contract is written in the Solidity programming language and run on the Ethereum network.
Srinath Setty
This paper introduces Spartan, a new family of zero-knowledge succinct non-interactive arguments of knowledge (zkSNARKs) for the rank-1 constraint satisfiability (R1CS), an NP-complete language that generalizes arithmetic circuit satisfiability. A distinctive feature of Spartan is that it offers the first zkSNARKs without trusted setup (i.e., transparent zkSNARKs) for NP where verifying a proof incurs sub-linear costs—without requiring uniformity in the NP statement’s structure. Furthermore, Spartan offers zkSNARKs with a time-optimal prover, a property that has remained elusive for nearly all zkSNARKs in the literature.
Wolf Posdorfer, Julian Kalinowski
No abstract is available for this record.
Jusik Yun, Yunyeong Goh, Jong‐Moon Chung
Blockchains guarantee data integrity through consensus of distributed ledgers based on multiple validation nodes called miners. For this reason, any blockchain system can be critically disabled by a malicious attack from a majority of the nodes (e.g., 51% attack). These attacks are more likely to succeed as the number of nodes required for consensus is smaller. Recently, as blockchains are becoming too large (making them difficult to store, send, receive, and manage), sharding is being considered as a technology to help improve the transaction throughput and scalability of blockchains. Sharding distributes block validators to disjoint sets to process transactions in parallel. Therefore, the number of validators of each shard group is smaller, which makes shard-based blockchains more vulnerable to 51% attacks than blockchains that do not use sharding. To solve this problem, this paper proposes a trust-based shard distribution (TBSD) scheme that assigns potential malicious nodes in the network to different shards, preventing malicious nodes from gaining a dominating influence on the consensus of a single shard. TBSD uses a trust-based shard distribution scheme to prevent malicious miners from gathering in on one shard by integration of a trust management system and genetic algorithm (GA). First, the trust of all nodes is computed based on the previous consensus result. Then, a GA is used to compute the shard distribution set to prevent collusion of malicious miners. The performance evaluation shows that the proposed TBSD scheme results in a shard distribution with a higher level of fairness than existing schemes, which provides an improved level of protection against malicious attacks.
Miraz Uz Zaman, Tong Shen, Manki Min
In this paper, we present the idea of proof of sincerity for a new consensus method for mobile-user-friendly blockchains. Ever since the birth of Bitcoin, there have been many distributed consensus methods studied to replace the central (or third-party) trusts to protect the integrity of the distributed ledgers. Existing methods show pros and cons but none of them showed a proper balance between the imbalance of wealth and the security of the ledgers. In proof of sincerity, by allowing each and every entity even with smaller computing power to get rewarded by mining, we can effectively prevent the extreme imbalance of the wealth (often caused by the mining that is dominated by a small number of huge resource owners). At the same time, by maintaining the appropriate level of sincerity in terms of the combination of the number of miners and the level of each mining work, we can effectively maintain the security level of the distributed ledgers.
Vicent Cholvi, Antonio Fernández Anta, Chryssis Georgiou, Nicolas Nicolaou
This work provides a proper formalization for Distributed Ledger Objects (as first defined in [Antonio Fernández Anta et al., 2018]), when processes may be Byzantine. The formal definitions are accompanied by algorithms to implement Byzantine Distributed Ledgers by utilizing a Byzantine Atomic Broadcast service.
Peng Zhang, Douglas C. Schmidt, Jules White, Abhishek Dubey
No abstract is available for this record.
Alexander Binun, Shlomi Dolev, Tal Hadad
No abstract is available for this record.