The Experts below are selected from a list of 9705 Experts worldwide ranked by ideXlab platform
Wuhui Chen - One of the best experts on this subject based on the ideXlab platform.
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skychain a deep reinforcement learning empowered dynamic blockchain Sharding system
International Conference on Parallel Processing, 2020Co-Authors: Jianting Zhang, Zicong Hong, Xiaoyu Qiu, Yufeng Zhan, Song Guo, Wuhui ChenAbstract:To overcome the limitations on the scalability of current blockchain systems, Sharding is widely considered as a promising solution that divides the network into multiple disjoint groups processing transactions in parallel to improve throughput while decreasing the overhead of communication, computation, and storage. However, most existing blockchain Sharding systems adopt a static Sharding policy that cannot efficiently deal with the dynamic environment in the blockchain system, i.e., joining and leaving of nodes, and malicious attack. This paper presents SkyChain, a novel dynamic Sharding-based blockchain framework to achieve a good balance between performance and security without compromising scalability under the dynamic environment. We first propose an adaptive ledger protocol to guarantee that the ledgers can merge or split efficiently based on the dynamic Sharding policy. Then, to optimize the Sharding policy under dynamic environment with high dimensional system states, a deep reinforcement learning-based Sharding approach has been proposed, the goals of which include: 1) building a framework to evaluate the blockchain Sharding systems from the aspects of performance and security; 2) adjusting the re-Sharding interval, shard number and block size to maintain a long-term balance of the system’s performance and security. Experimental results show that SkyChain can effectively improve the performance and security of the Sharding system without compromising scalability under the dynamic environment in the blockchain system.
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ICPP - SkyChain: A Deep Reinforcement Learning-Empowered Dynamic Blockchain Sharding System
49th International Conference on Parallel Processing - ICPP, 2020Co-Authors: Jianting Zhang, Zicong Hong, Xiaoyu Qiu, Yufeng Zhan, Song Guo, Wuhui ChenAbstract:To overcome the limitations on the scalability of current blockchain systems, Sharding is widely considered as a promising solution that divides the network into multiple disjoint groups processing transactions in parallel to improve throughput while decreasing the overhead of communication, computation, and storage. However, most existing blockchain Sharding systems adopt a static Sharding policy that cannot efficiently deal with the dynamic environment in the blockchain system, i.e., joining and leaving of nodes, and malicious attack. This paper presents SkyChain, a novel dynamic Sharding-based blockchain framework to achieve a good balance between performance and security without compromising scalability under the dynamic environment. We first propose an adaptive ledger protocol to guarantee that the ledgers can merge or split efficiently based on the dynamic Sharding policy. Then, to optimize the Sharding policy under dynamic environment with high dimensional system states, a deep reinforcement learning-based Sharding approach has been proposed, the goals of which include: 1) building a framework to evaluate the blockchain Sharding systems from the aspects of performance and security; 2) adjusting the re-Sharding interval, shard number and block size to maintain a long-term balance of the system’s performance and security. Experimental results show that SkyChain can effectively improve the performance and security of the Sharding system without compromising scalability under the dynamic environment in the blockchain system.
Jianting Zhang - One of the best experts on this subject based on the ideXlab platform.
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skychain a deep reinforcement learning empowered dynamic blockchain Sharding system
International Conference on Parallel Processing, 2020Co-Authors: Jianting Zhang, Zicong Hong, Xiaoyu Qiu, Yufeng Zhan, Song Guo, Wuhui ChenAbstract:To overcome the limitations on the scalability of current blockchain systems, Sharding is widely considered as a promising solution that divides the network into multiple disjoint groups processing transactions in parallel to improve throughput while decreasing the overhead of communication, computation, and storage. However, most existing blockchain Sharding systems adopt a static Sharding policy that cannot efficiently deal with the dynamic environment in the blockchain system, i.e., joining and leaving of nodes, and malicious attack. This paper presents SkyChain, a novel dynamic Sharding-based blockchain framework to achieve a good balance between performance and security without compromising scalability under the dynamic environment. We first propose an adaptive ledger protocol to guarantee that the ledgers can merge or split efficiently based on the dynamic Sharding policy. Then, to optimize the Sharding policy under dynamic environment with high dimensional system states, a deep reinforcement learning-based Sharding approach has been proposed, the goals of which include: 1) building a framework to evaluate the blockchain Sharding systems from the aspects of performance and security; 2) adjusting the re-Sharding interval, shard number and block size to maintain a long-term balance of the system’s performance and security. Experimental results show that SkyChain can effectively improve the performance and security of the Sharding system without compromising scalability under the dynamic environment in the blockchain system.
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ICPP - SkyChain: A Deep Reinforcement Learning-Empowered Dynamic Blockchain Sharding System
49th International Conference on Parallel Processing - ICPP, 2020Co-Authors: Jianting Zhang, Zicong Hong, Xiaoyu Qiu, Yufeng Zhan, Song Guo, Wuhui ChenAbstract:To overcome the limitations on the scalability of current blockchain systems, Sharding is widely considered as a promising solution that divides the network into multiple disjoint groups processing transactions in parallel to improve throughput while decreasing the overhead of communication, computation, and storage. However, most existing blockchain Sharding systems adopt a static Sharding policy that cannot efficiently deal with the dynamic environment in the blockchain system, i.e., joining and leaving of nodes, and malicious attack. This paper presents SkyChain, a novel dynamic Sharding-based blockchain framework to achieve a good balance between performance and security without compromising scalability under the dynamic environment. We first propose an adaptive ledger protocol to guarantee that the ledgers can merge or split efficiently based on the dynamic Sharding policy. Then, to optimize the Sharding policy under dynamic environment with high dimensional system states, a deep reinforcement learning-based Sharding approach has been proposed, the goals of which include: 1) building a framework to evaluate the blockchain Sharding systems from the aspects of performance and security; 2) adjusting the re-Sharding interval, shard number and block size to maintain a long-term balance of the system’s performance and security. Experimental results show that SkyChain can effectively improve the performance and security of the Sharding system without compromising scalability under the dynamic environment in the blockchain system.
Mustapha Samih - One of the best experts on this subject based on the ideXlab platform.
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A Novel Methodology-Based Joint Hypergeometric Distribution to Analyze the Security of Sharded Blockchains
IEEE Access, 2020Co-Authors: Abdelatif Hafid, Abdelhakim Hafid, Mustapha SamihAbstract:Cryptocurrencies (e.g., Bitcoin and Ethereum), which promise to become the future of money transactions, are mainly implemented with blockchain technology. However, blockchain suffers from scalability issues. Sharding is the leading solution for blockchain scalability. Sharding splits the blockchain network into sub-chains called shards/committees. Each shard processes a sub-set of transactions, rather than the entire network processing all transactions. This raises security issues for Sharding-based blockchain protocols. In this paper, we propose a novel methodology to analyze the security of these protocols (e.g., OmniLedger and RapidChain). In particular, this methodology estimates the failure probability of one Sharding round taking into consideration the failure probabilities of all shards. To illustrate the effectiveness of the estimated failure probability, we conduct a numerical analysis of our methodology based on a huge number of trials. Finally, we compute confidence intervals to accurately estimate the failure probability and compare our methodology with existing approaches.
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New Mathematical Model to Analyze Security of Sharding-Based Blockchain Protocols
IEEE Access, 2019Co-Authors: Abdelatif Hafid, Abdelhakim Senhaji Hafid, Mustapha SamihAbstract:In recent years, the scalability issue of blockchain protocols has received huge attention. Sharding is one of the most promising solutions to scale blockchain. The basic idea behind Sharding is to divide the blockchain network into multiple committees where each committee processes a separate set of transactions. In this paper, we propose a mathematical model to analyze the security of Sharding-based blockchain protocols. Moreover, we analyze well-known Sharding protocols including RapidChain, OmniLedger, and Zilliga to validate our model. The key contribution of our paper is to bound the failure probability for one committee and so for each epoch using probability bounds for sums of upper-bounded hypergeometric and binomial distributions. In addition, this paper contribution answers the following fundamental question: “how to keep the failure probability, for a given Sharding protocol, smaller than a predefined threshold?”. Three probability bounds are used: Chebyshev, Hoeffding, and Chvátal. To illustrate the effectiveness of our proposed model, we conduct a numerical and comparative analysis of the proposed bounds.
Gang Wang - One of the best experts on this subject based on the ideXlab platform.
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repshard reputation based Sharding scheme achieves linearly scaling efficiency and security simultaneously
2020 IEEE International Conference on Blockchain (Blockchain), 2020Co-Authors: Gang WangAbstract:Sharding technology is becoming a promising candidate to address the scalability issues in blockchain. The key concept behind Sharding technology is to partition the network status into multiple distinct smaller committees, each of which handles a disjoint set of transactions to leverage its capability of parallel processing. However, when introducing Sharding technology to blockchain, several key challenges need to be resolved, such as security and heterogeneity among the participating nodes. This paper introduces RepShard, a reputation-based blockchain Sharding scheme that aims to achieve both linearly scaling efficiency and system security simultaneously. RepShard adopts a two-layer hierarchical chain structure, consisting of a reputation chain and independent transaction chains. Each transaction chain is maintained within its shard to record transactions, while the reputation chain is maintained by all shards to update the reputation score of each participating node. We leverage a novel reputation scheme to record each participating node’s integrated and valid contribution to the system, in which we consider the heterogeneity of participating nodes (e.g., computational resources). The reputation score used in Sharding and leader election processes maintains the balance and security of each shard. RepShard relies on verifiable relay transactions for cross-shard transactions to ensure consistency between distinct shards. By integrating reputation into the Sharding protocol, our scheme can offer both scalability and security at the same time.
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RandChain: Practical Scalable Decentralized Randomness Attested by Blockchain
2020 IEEE International Conference on Blockchain (Blockchain), 2020Co-Authors: Gang Wang, Mark NixonAbstract:Reliable and verifiable public randomness is not only an essential building block in various cryptographic primitives, but also is a critical component in many distributed and decentralized protocols, e.g., blockchain Sharding. A `good' randomness generator should preserve several distinctive properties, such as public-verifiability, bias-resistance, unpredictability, and availability. However, it is a challenging task to generate such good randomness. For instance, a dishonest party may behave deceptively to bias the final randomness, which is toward his preferences. And this challenge is more serious in a distributed and decentralized system. Blockchain technology provides several promising features, such as decentralization, immutability, and trustworthiness. Due to extremely high overheads on both communication and computation, most existing solutions face an additional scalability issue. We propose a Sharding-based scheme, RandChain, to obtain a practical scalable distributed and decentralized randomness attested by blockchain in large-scale applications. In RandChain, we eliminate the use of computation-heavy cryptographic operations, e.g., Publicly Verifiable Secret Sharing (PVSS), in prevalent approaches. We build a sub-routine, RandGene, which utilizes a commit-then-reveal strategy to establish a local randomness, enforced by efficient Verifiable Random Function (VRF). RandGene generates the randomness based on statistical approaches, instead of cryptographic operations, to eliminate computational operations. RandChain maintains a two-layer hierarchical chain structure via a Sharding scheme. The first level chain is maintained by RandGene within each shard to provide a verifiable randomness source by blockchain. The second level chain uses the randomnesses from each shard to build a randomness chain.
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Blockchain - RepShard: Reputation-based Sharding Scheme Achieves Linearly Scaling Efficiency and Security Simultaneously
2020 IEEE International Conference on Blockchain (Blockchain), 2020Co-Authors: Gang WangAbstract:Sharding technology is becoming a promising candidate to address the scalability issues in blockchain. The key concept behind Sharding technology is to partition the network status into multiple distinct smaller committees, each of which handles a disjoint set of transactions to leverage its capability of parallel processing. However, when introducing Sharding technology to blockchain, several key challenges need to be resolved, such as security and heterogeneity among the participating nodes. This paper introduces RepShard, a reputation-based blockchain Sharding scheme that aims to achieve both linearly scaling efficiency and system security simultaneously. RepShard adopts a two-layer hierarchical chain structure, consisting of a reputation chain and independent transaction chains. Each transaction chain is maintained within its shard to record transactions, while the reputation chain is maintained by all shards to update the reputation score of each participating node. We leverage a novel reputation scheme to record each participating node’s integrated and valid contribution to the system, in which we consider the heterogeneity of participating nodes (e.g., computational resources). The reputation score used in Sharding and leader election processes maintains the balance and security of each shard. RepShard relies on verifiable relay transactions for cross-shard transactions to ensure consistency between distinct shards. By integrating reputation into the Sharding protocol, our scheme can offer both scalability and security at the same time.
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sok Sharding on blockchain
IACR Cryptology ePrint Archive, 2019Co-Authors: Gang Wang, Zhijie Jerry Shi, Mark J Nixon, Song HanAbstract:Blockchain is a distributed and decentralized ledger for recording transactions. It is maintained and shared among the participating nodes by utilizing cryptographic primitives. A consensus protocol ensures that all nodes agree on a unique order in which records are appended. However, current blockchain solutions are facing scalability issues. Many methods, such as Off-chain and Directed Acyclic Graph (DAG) solutions, have been proposed to address the issue. However, they have inherent drawbacks, e.g., forming parasite chains. Performance, such as throughput and latency, is also important to a blockchain system. Sharding has emerged as a good candidate that can overcome both the scalability and performance problems in blockchain. To date, there is no systematic work that analyzes the Sharding protocols. To bridge this gap, this paper provides a systematic and comprehensive review on blockchain Sharding techniques. We first present a general design flow of Sharding protocols and then discuss key design challenges. For each challenge, we analyze and compare the techniques in state-of-the-art solutions. Finally, we discuss several potential research directions in blockchain Sharding.
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AFT - SoK: Sharding on Blockchain
Proceedings of the 1st ACM Conference on Advances in Financial Technologies, 2019Co-Authors: Gang Wang, Zhijie Jerry Shi, Mark J Nixon, Song HanAbstract:Blockchain is a distributed and decentralized ledger for recording transactions. It is maintained and shared among the participating nodes by utilizing cryptographic primitives. A consensus protocol ensures that all nodes agree on a unique order in which records are appended. However, current blockchain solutions are facing scalability issues. Many methods, such as Off-chain and Directed Acyclic Graph (DAG) solutions, have been proposed to address the issue. However, they have inherent drawbacks, e.g., forming parasite chains. Performance, such as throughput and latency, is also important to a blockchain system. Sharding has emerged as a good candidate that can overcome both the scalability and performance problems in blockchain. To date, there is no systematic work that analyzes the Sharding protocols. To bridge this gap, this paper provides a systematic and comprehensive review on blockchain Sharding techniques. We first present a general design flow of Sharding protocols and then discuss key design challenges. For each challenge, we analyze and compare the techniques in state-of-the-art solutions. Finally, we discuss several potential research directions in blockchain Sharding.
Song Guo - One of the best experts on this subject based on the ideXlab platform.
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skychain a deep reinforcement learning empowered dynamic blockchain Sharding system
International Conference on Parallel Processing, 2020Co-Authors: Jianting Zhang, Zicong Hong, Xiaoyu Qiu, Yufeng Zhan, Song Guo, Wuhui ChenAbstract:To overcome the limitations on the scalability of current blockchain systems, Sharding is widely considered as a promising solution that divides the network into multiple disjoint groups processing transactions in parallel to improve throughput while decreasing the overhead of communication, computation, and storage. However, most existing blockchain Sharding systems adopt a static Sharding policy that cannot efficiently deal with the dynamic environment in the blockchain system, i.e., joining and leaving of nodes, and malicious attack. This paper presents SkyChain, a novel dynamic Sharding-based blockchain framework to achieve a good balance between performance and security without compromising scalability under the dynamic environment. We first propose an adaptive ledger protocol to guarantee that the ledgers can merge or split efficiently based on the dynamic Sharding policy. Then, to optimize the Sharding policy under dynamic environment with high dimensional system states, a deep reinforcement learning-based Sharding approach has been proposed, the goals of which include: 1) building a framework to evaluate the blockchain Sharding systems from the aspects of performance and security; 2) adjusting the re-Sharding interval, shard number and block size to maintain a long-term balance of the system’s performance and security. Experimental results show that SkyChain can effectively improve the performance and security of the Sharding system without compromising scalability under the dynamic environment in the blockchain system.
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ICPP - SkyChain: A Deep Reinforcement Learning-Empowered Dynamic Blockchain Sharding System
49th International Conference on Parallel Processing - ICPP, 2020Co-Authors: Jianting Zhang, Zicong Hong, Xiaoyu Qiu, Yufeng Zhan, Song Guo, Wuhui ChenAbstract:To overcome the limitations on the scalability of current blockchain systems, Sharding is widely considered as a promising solution that divides the network into multiple disjoint groups processing transactions in parallel to improve throughput while decreasing the overhead of communication, computation, and storage. However, most existing blockchain Sharding systems adopt a static Sharding policy that cannot efficiently deal with the dynamic environment in the blockchain system, i.e., joining and leaving of nodes, and malicious attack. This paper presents SkyChain, a novel dynamic Sharding-based blockchain framework to achieve a good balance between performance and security without compromising scalability under the dynamic environment. We first propose an adaptive ledger protocol to guarantee that the ledgers can merge or split efficiently based on the dynamic Sharding policy. Then, to optimize the Sharding policy under dynamic environment with high dimensional system states, a deep reinforcement learning-based Sharding approach has been proposed, the goals of which include: 1) building a framework to evaluate the blockchain Sharding systems from the aspects of performance and security; 2) adjusting the re-Sharding interval, shard number and block size to maintain a long-term balance of the system’s performance and security. Experimental results show that SkyChain can effectively improve the performance and security of the Sharding system without compromising scalability under the dynamic environment in the blockchain system.