Reputation-based Blockchain Sharding Consensus Scheme by WANG Meng-nan, HUANG Jian-hua, SHAO Xing-hui, MAI Yong

“…Sharding is a technology that solves the problem of blockchain capacity expansion.However,sharding may make it ea-sier for malicious nodes to be concentrated in a single shard,thus hindering the safe operation of the entire system.This paper proposes a reputation-based sharding consensus protocol(RBSCP),which establishes a reputation mechanism to measure node behavior and encourage nodes to follow the protocol.The reputation level-based sharding method reduces the difference in the reputation level distribution in different shards,so as to prevent malicious nodes from concentrating on a single shard to do evil.A double-chain model combining verification chain and record chain is proposed.Through the differentiated storage of transactions,the storage capacity of the blockchain is expanded while the security of the blockchain is improved.By associating the vo-ting shares with the node reputation and differentiating the node commitments,a reputation-based fast Byzantine fault tolerance(RFBFT) algorithm is proposed,which enables honest nodes to reach consensus faster and reduces the impact of malicious nodes.Security analysis shows that RBSCP can guarantee the rationality of node distribution in shards and the security of consensus process,and prevent double spend attack and nothing at stake attack.Experimental results show that RBSCP can achieve low sharding latency,low consensus latency and high throughput under the premise of ensuring security.…”
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Shard Load Balancing Method Using State Reduction by CHEN Jing, LI Zhi-huai, GAO Dong-xue, LI Min

“…Sharding technology is one of the core technologies to solve the scalability problem of blockchain.When transactions in the P2P network are aggregated into established shards according to the rules,and the verification nodes are randomly and evenly distributed to each shard,the transactions in this shard may be congested because the transaction verification load of individual shard may far exceed the average load.In order to solve the load imbalance between shards,a shard load balancing method using state reduction is proposed.Firstly,the state reduction model is given,which allows high-performance nodes to store more adjacent states,and the node performance is roughly classified according to this model.Secondly,according to the transaction verification situation in each timeslot,unverified transactions are taken as the remaining load,which is used as the basis for adjusting the verification ability in the next timeslot.Finally,the nodes are scored and graded,and the node selection strategy is given based on the remaining load and the average score of the consensus verification node set.Nodes are allocated reasonably and randomly,and the remaining loads of high load fragments are reduced upward.Experimental verification shows that the shard load balancing method using state reduction effectively balances the unusual load of one shard without reducing the transaction verification rate of a single shard.…”
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Decentralized Storage with Access Control and Data Persistence for e-Book Stores by Keigo Ogata, Satoshi Fujita

“…In addition, e-book data stored on storage nodes in the distributed storage is divided into shards using Reed–Solomon codes, and each storage node stores only a single shard, thereby preventing the creation of nodes that can restore the entire content from locally stored data. …”
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Smoking guns and volcanic ash: the importance of sparse tephras in Greenland ice cores by Gill Plunkett, Michael Sigl, Jonathan R. Pilcher, Joseph R. McConnell, Nathan Chellman, J.P. Steffensen, Ulf Büntgen

“…A solitary ash shard whose major element geochemistry is consistent with Katla corroborates the attribution of the 822±1 CE sulphur peak to this source, clearly showing that a single shard can signify primary ashfall. Other tephras are present in similarly low abundances, but their geochemistries are less certainly attributable to specific sources. …”
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Volcanic glass from the 1.8 ka Taupō eruption (New Zealand) detected in Antarctic ice at ~ 230 CE by Stephen B. Piva, Simon J. Barker, Nels A. Iverson, V. Holly L. Winton, Nancy A. N. Bertler, Michael Sigl, Colin J. N. Wilson, Nelia W. Dunbar, Andrei V. Kurbatov, Lionel Carter, Bruce L. A. Charlier, Rewi M. Newnham

“…Six shards of a distinctive geochemical composition, identical within analytical uncertainties to proximal Taupō glass, are accompanied by a single shard indistinguishable from glass of the ~25.5 ka Ōruanui supereruption, also from Taupō volcano. …”
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