Consensus - loosely defined as global agreement on the state of a decentralised network across its mutually untrusting participants - is an essential ingredient for decentralisation. At the same time, its scalability remains the Achilles' heel of distributed systems. A number of ongoing R&D efforts aim at scaling blockchain networks up to hundreds of thousands of transactions per second. Yet even such performance targets can be seen as modest when the goal is to bring traditional web workloads to the decentralised web (Web3), requiring the handling of billions of transactions per second, large volumes of data, complex workloads and applications, and hard latency requirements. The goal of this workshop is to foster scientific exchange across a wider community in consensus research and adjacent fields, by disseminating and providing a forum for discussion of upcoming impactful research with a practical twist.
Cesar Castellon Escobar, Swapnoneel Roy, O. Patrick Kreidl, Ayan Dutta · 5 authors
Blockchain-powered smart systems deployed in different industrial applications promise operational efficiencies and improved yields, while significantly mitigating cybersecurity risks. Tradeoffs between availability and security arise at implementation, however, triggered by the additional resources (e.g., memory and computation) required by blockchain-enabled hosts. This paper applies an energy-reducing algorithmic engineering technique for Merkle Tree (MT) root calculations and the Proof of Work (PoW) algorithm, two principal elements of blockchain computations, as a means to preserve the promised security benefits but with less compromise to system availability. Using pyRAPL, a python library to measure the energy consumption of a computation, we experiment with both the standard and energy-reduced implementations of both algorithms for different input sizes. Our results show that up to 98% reduction in energy consumption is possible within the blockchain’s MT construction module, with the benefits typically increasing with larger input sizes. For the PoW algorithm, our results show up to 20% reduction in energy consumption, with the benefits being lower for higher difficulty levels. The proposed energy-reducing technique is also applicable to other key elements of blockchain computations, potentially affording even “greener” blockchain-powered systems than implied by only the results obtained thus far on the MT and PoW algorithms.
Yunshu Liu, Shulin Ke, Zhixuan Fang, Man Hon Cheung · 6 authors
In current blockchain systems, the transaction fee is often not enough to cover the storage cost, jeopardizing blockchain sustainability in the long run. Such a storage sustainability issue is partially due to miners’ heterogeneous storage costs and users’ low-intensity fee competition. Motivated by these two observations, we propose a Fee and Transaction Expiration Time (FTET) mechanism to alleviate this issue. Specifically, we model the blockchain operation as a three-stage game. In Stage I, the system designer proposes the storage sustainability mechanism. In Stage II, each user decides whether to propose transactions and the corresponding transaction fees. In Stage III, each miner decides which transactions to include in the block. Although the analysis of the heterogeneous miner interaction is technically challenging, we fully solve it in closed-form motivated by how miners select transactions in practice. The equilibrium analysis reveals that high-storage-cost miners admit transactions with fees above a time-increasing threshold. Under the optimal FTET mechanism, the blockchain system can achieve the storage sustainability without any social welfare loss, comparing with the maximum achievable social welfare without the storage sustainability constraint. Moreover, the optimal FTET mechanism achieves a higher social welfare than the fee mechanism in current practice by selectively rejecting some transactions suffering high delays. Finally, we implement a blockchain prototype to compare the performance of the optimal FTET mechanism with the mining round time adjustment (MRTA) mechanism. The optimal FTET mechanism achieves higher social welfare (94.5% on average) and better storage sustainability. We find that more pending transactions may lead to lower transaction fees.
K. Vanitha, Subhashish Goswami, TNVRSwamy, K. Chitra Chellam · 6 authors
Blockchain Technology has acquired notoriety in both scholar and industry due to its decentralized, versatile, security and irrefutable characteristics. The blockchain is a disseminated data set that holds record of exchanges that are conveyed among members in its most essential structure. Manufactured exchanges can't pass aggregate certification since every exchange requires the understanding of various individuals. A record can never be changed or erased after it has been made and recognized by the blockchain. After the Internet, blockchain innovation is presently viewed as the main development. The previous could tackle the trust issue utilizing shared systems administration and public-key cryptography assuming the last option interfaces individuals to all the more likely comprehend online business processes. The objective of this paper is to take a gander at the critical instances of blockchain innovation's comprehensive effect and see it as an inseparable part of our daily existences.
Since executing a smart contract on the Ethereum blockchain costs money (measured in gas ), smart contract developers spend significant effort in reducing gas usage. In this paper, we propose a new technique for reducing the gas usage of smart contracts by changing the underlying data layout. Given a smart contract P and a type-level transformation, our method automatically synthesizes a new contract P ′ that is functionally equivalent to P . Our approach provides a convenient DSL for expressing data type refactorings and employs program synthesis to generate the new version of the contract. We have implemented our approach in a tool called Solidare and demonstrate its capabilities on real-world smart contracts from Etherscan and GasStation. In particular, we show that our approach is effective at automating the desired data layout transformation and that it is useful for reducing gas usage of smart contracts that use rich data structures.
Blockchain systems became popular, not just because they provide the underlying mechanism of the most prominent cryptocurrencies. They provide temper resistant features with decentralised architecture that are useful for many Internet of Things applications. However, one of the most limiting factors of its usability, are the slow throughput and latency. Even in Bit-coin, the most popular blockchain-based cryptocurrency system, speed causes a serious problem. Performance measurements and analysis are crucial to reveal possible bottlenecks and trigger improvements. They can also be used to compare different services with similar purposes. The goal of this paper is to find a way to differentiate blockchain services with a novel, lightweight approach. We developed a wallet application to be able to carry out experimental measurements by executing parameterizable computational tasks with smart contracts. We performed an evaluation of four different blockchain implementations with our approach, and investigated the correlation between the computational need of the smart contract and the elapsed time or used gas, and compared the overall latency.
Blockchain and distributed ledger technologies are gaining the interest of the academy, companies, and institutions. Nonetheless, the path toward blockchain adoption is not straightforward, as blockchain is a complex technology that requires revisiting the standard way of addressing problems and tackling them from a decentralized perspective. Thus, decision-makers adopt blockchain technology for the wrong reasons or prefer it to more suitable ones. This work presents a decision framework for blockchain adoption to help decision-makers decide whether blockchain is applicable, valuable, and preferable to other technologies. In particular, The decision framework is composed of a small set of questions that can be answered from a managerial standpoint and that do not require a deep technical knowledge of blockchain-related topics.
Ethereum is one of the most actively used blockchain platforms that supports various decentralized services such as DeFi, NFT, and the Metaverse. Such services are enabled by Solidity smart contracts. A block is mined by executing a batch of transactions and reaching an agreement among consensus nodes. However, since the execution model of Ethereum is Order-Execute, all transactions must be ordered first and executed sequentially, resulting in limited block feed to consensus phase. This may lead to underutilization of consensus capacity. In this paper, we propose a parallel execution model for Solidity smart contracts using append-only shared logs. The parallel execution model consists of the following components: (1) key-value state sharding, (2) Solidity simulation module for each shard, (3) append-only log shared among Solidity simulation module; Append-only log stores the read-write set of a transaction in each entry, (4) the block mining module that is responsible for creating a block based on the shared log information and initiating the block consensus phase.
The popularity of Blockchain is rising on account of its far-reaching applications in diverse industries. However, recently, blockchain has seen a rise of energy extensive mining pools which is leading to centralization, contradicting the basic blockchain tenet of decentralization. This letter proposes a novel consensus algorithm using Proof of Majority (PoM), to increase decentralization and to eliminate resource-intensive tasks leading to a reduced carbon footprint. We have evaluated the proposed algorithm in terms of latency and throughput. The proposed consensus algorithm outperforms popular existing consensus algorithms.
Blockchain performance cannot meet the requirement nowadays. One of the crucial ways to improve performance is sharding. However, most blockchain sharding research focuses on the public blockchain. As for consortium blockchain, previous studies cannot support high cross-shard efficiency, multiple-shard contract calling, strict transaction atomicity, and shard availability, which are essential requirements but also challenges in consortium blockchain systems. Facing these challenges, we propose Meepo, a systematic study on sharded consortium blockchain. Meepo enhances cross-shard efficiency via the cross-epoch and cross-call. Moreover, a partial cross-call merging strategy is designed to handle the multi-state dependency in contract calls, achieving flexible multiple-shard contract calling. Meepo employs a replay-epoch to ensure strict transaction atomicity, and it also uses a backup algorithm called shadow shard based recovery to improve the shard robustness. On a test-bed of 128 AliCloud servers, setting 32 shards and 4 consortium members, Meepo-OpenEtheruem can achieve more than 140,000 cross-shard TPS under the workload of 100,000,000 asset transactions. It also shows more than 50,000 TPS under the transactions of real-world shopping behaviors.
As transaction fees skyrocket today, blockchains become increasingly expensive, hurting their adoption in broader applications. This work tackles the saving of transaction fees for economic blockchain applications. The key insight is that other than the existing "default" mode to execute application logic fully on-chain, i.e., in smart contracts, and in fine granularity, i.e., user request per transaction, there are alternative execution modes with advantages in cost-effectiveness. On Ethereum, we propose a holistic middleware platform supporting flexible and secure transaction executions, including off-chain states and batching of user requests. Furthermore, we propose control-plane schemes to adapt the execution mode to the current workload for optimal runtime cost. We present a case study on the institutional accounts (e.g., coinbase.com) intensively sending Ether on Ethereum blockchains. By collecting real-life transactions, we construct workload benchmarks and show that our work saves 18% ~ 47% per invocation than the default baseline while introducing 1.81 ~ 16.59 blocks delay.
With the development of Blockchain technology, permissioned Blockchains are getting more and more attention from researchers because applications based on permissioned Blockchains are more practical and easier to be carried out. This paper aims to design a dedicated consensus protocol for permissioned Blockchains. The existing consensus protocols applied to permissioned Blockchains are either derived from public Blockchains such as Proof of Work (PoW) or Proof of Stake (PoS), with full decentralization, resulting in low transaction processing efficiency; or derived from traditional Byzantine fault-tolerant (BFT) consensus protocols such as Practical BFT (PBFT) or HoneyBadgerBFT, with high communication complexity of the consensus process, resulting in low scalability. Therefore, we propose a dedicated consensus protocol for permissioned Blockchains called Votes-as-a-Proof (VaaP) with high transaction processing efficiency while ensuring high scalability. Every node in VaaP runs a simple consensus process based on voting in parallel. Faulty nodes will only deprive themselves of using consensus service. We present the comparison of VaaP and Sphinx, one of the state-of-the-art consensus protocols, analytically and experimentally (up to 500 nodes). The results indicate that VaaP outperforms Sphinx in throughput, latency and scalability.
Sustainable, immutable, and affordable data storage to leading universities, research institutions, enterprises, and Web3 organizations. The next generation of platforms will be built on the decentralized web. Unlocking the benefits of the next economy: True ownership, security, and verifiability of data.
Benedikt Severin, Marc Hesenius, Florian Blum, Michael Hettmer · 5 authors
Users must pay a fee depending on resource consumption when using smart contracts on the Ethereum blockchain. As even the most basic operations cost several dollars under moderate network load, developers may actively reduce user-paid fees by optimizing the smart contract resource consumption (’gas costs’). Previous works suggested patterns and tools supporting developers in gas cost optimization, but up to now a comprehensive analysis of their real-world impact is missing. Another gap is the maintenance and evolution support for smart contracts leveraging the publicly available usage data. We propose high-level gas cost profiles and review which profiles are considered in the existing literature. Additionally, we sampled around 68,000 smart contract interactions from three years, analyzed them using the gas cost profiles, and compare the findings to the current focus in literature. In our data set, external code, storage, and the transaction base fee are first-level cost drivers in terms of absolute gas usage, but contract deployment becomes also costly when considering the average gas usage per transaction. Our analysis also shows that plenty of previous work focused cost categories barely influencing resource consumption.
This research presents a novel method to assess inter-chain message relay time in the Cosmos blockchain network, which employs the Inter-Blockchain Communication (IBC) protocol for blockchain interoperability. While inter-chain transactions in Cosmos lag behind intra-chain transactions, this research conducts a thorough performance evaluation, emphasizing message relay time across diverse Cosmos chains. The results show a strong association between inter-chain transaction frequency and overall transaction processing speed (TPS), underscoring the inherent trade-off between scalability and compatibility in inter-chain communication protocols. A thorough understanding of inter-chain transaction performance is essential for advancing interoperability and improving cross-blockchain network designs. As a result, this research improves our understanding of Cosmos’ functionality and provides insightful recommendations for boosting the effectiveness and scalability of inter-chain communication. The study also sheds light on message delivery patterns in the Cosmos ecosystem, showing that IBC message relay time has an average duration of 55.448 s and is distributed lognormally. Notably, the time between the commitment of the IBC RecvPacket transaction and the commitment of the IBC Acknowledgement transaction (R to A time) considerably impacts the effectiveness of message transmission, which causes delays in the IBC message relay process.
Xi Chen, David Simchi‐Levi, Zishuo Zhao, Yuan Zhou
In blockchain systems, the design of transaction fee mechanisms is essential for stability and satisfaction for both miners and users. A recent work has proven the impossibility of collusion-proof mechanisms that achieve both non-zero miner revenue and Dominating-Strategy-Incentive-Compatible (DSIC) for users. However, a positive miner revenue is important in practice to motivate miners. To address this challenge, we consider a Bayesian game setting and relax the DSIC requirement for users to Bayesian-Nash-Incentive-Compatibility (BNIC). In particular, we propose an auxiliary mechanism method that makes connections between BNIC and DSIC mechanisms. With the auxiliary mechanism method, we design a transaction fee mechanism (TFM) based on the multinomial logit (MNL) choice model, and prove that the TFM has both BNIC and collusion-proof properties with an asymptotic constant-factor approximation of optimal miner revenue for i.i.d. bounded valuations. Our result breaks the zero-revenue barrier while preserving truthfulness and collusion-proof properties.
The paper firstly takes the requirements of the college education integrity system (CEIS) issued by the local education authority as the research object, proposes a restricted blockchain model with auditing and its consensus algorithm, and then proposes two improved MPT tree search algorithms to improve the search efficiency. Finally, the system adopts the Ethereum blockchain for system design, implementation and verification. The system is deployed in the NodeJS, with the Truffle framework to configure and write smart contracts to create decentralized DApp. The front-end is built with LAYUI, and the back-end is written in Solidity for smart contracts. MongoDB and Redis are used for data interaction with DApp. Ganache is used to build an Ethereum simulation network for system testing and realize the application and transfer of Ethereum in units of accounts. The blockchain-based college integrity system can solve the problems of high cost, low efficiency and data reliability risks in centralized systems.
Abstract This study proposes a primary node election method based on probabilistic linguistic term set (PLTS) for the practical Byzantine fault tolerance (PBFT) consensus mechanism to effectively enhance the efficiency of reaching consensus. Specifically, a novel concept of the probabilistic linguistic term set with a confidence interval (PLTS-CI) is presented to express the uncertain complex voting information of nodes during primary node election. Then, a novel score function based on the exponential semantic value and confidence approximation value for the PLTS-CI, called Score-ESCA, is used to solve the problems of comparing different nodes with various voting attitudes. This method helps select the node with the highest score by utilizing complex decision attitudes, making it an accurate primary node election solution. Furthermore, the feasibility of our proposed method is proved by both theoretical analysis and experimental evaluations.
Yunming Xiao, Sarit Markovich, Aleksandar Kuzmanovic
Having enabled numerous applications, blockchains have attracted not only much attention, in the past decade, but also huge amount of resources: talent, capital, energy, etc. Focusing on the mining side of the market, in this paper, we aim at understanding how to efficiently use the resources mining and staking pools attract. We start with developing predictions about factors that increase the efficient allocation of pools' resources. We then test our predictions based on a general model for optimal resource allocation that we develop, as well as data we collected on pools' actual resource allocations. We find that pools can increase resource efficiency by mining for more blockchains as well as by increasing the frequency of resource re-allocation. Further, we enroll to mining pools as a miner to understand and comment on how pools can encourage their miners to increase the efficiency of their allocation. While our empirical investigation mostly focuses on the BTC family, we show that our theory and results are general and applicable to the Ethereum family as well as other proof-of-work (PoW) and proof-of-stake (PoS) chains.
The distributed ledger technology first introduced as a baseline technology for Bitcoin is disrupting many fields with its features of immutability and traceability. Applying blockchain in different fields is not one size fits for all solution. The various domains came up with different drawbacks of blockchain. To resolve these problems changes in block structures and consensus mechanisms of blockchain are proposed and used for different use cases or domains. We have proposed a consensus mechanism to reduce latency and increase the throughput of transactions processed by the blockchain network. The evaluation of the newly proposed consensus mechanism is done using queuing theory, mathematical models or simulations. Beyond this, we have used the Hyperledger platform to implement our proposed consensus mechanism Proof of Scope. The performance of implementations of Raft and PoW-Ethash consensus mechanisms from Hyperledger are evaluated with the proposed consensus mechanism. The varying load was applied to the network to measure transaction throughput. It is found that the latency is lower and throughput is better of the proposed consensus mechanism than that of Raft and PoW-Ethash for the same network conditions.
Michael Sober, Marten Sigwart, Philipp Frauenthaler, Christof Spanring · 6 authors
Abstract Today, several solutions for cross-blockchain asset transfers exist. However, these solutions are either tailored to specific assets or neglect finality guarantees that prevent assets from getting lost in transit. In this paper, we present a cross-blockchain asset transfer protocol that supports arbitrary assets, is adaptable to different means of cross-blockchain communication, and adheres to requirements such as finality. The ability to freely transfer assets between blockchains may increase transaction throughput and provide developers with more flexibility by allowing them to design digital assets that leverage the capacities and capabilities of multiple blockchains. We define the general requirements and specifications for a cross-blockchain asset transfer protocol and provide a proof-of-concept implementation for EVM-based blockchains. Further, we evaluate the protocol concerning costs, transfer duration, and security.