16399

14614

كارشناسي ارشد

نرم افزار

اصفهان : دانشگاه صنعتي اصفهان

1399

يازده، 78ص.: مصور، جدول، نمودار

محمد حسين منشئي

محمدرضا حيدرپور

1400/01/23

كتابنامه

مهندسي كامپيوتر

مهندسي برق و كامپيوتر

1400/01/23

2687747

Analyze and design effective incentives to improve the security and throughput of Algorand Blockchain Maryam Abbasi abbasi maryam@ec iut ac ir February 24 2021 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree Master of Science Language FarsiSupervisor Dr Mohammad Hossein Manshaie manshaei@cc iut ac ir AbstractAlgorand is a public blockchain that uses the proof of stack It has a throughput of 750 MB of transactionsper hour which is 125 times that of Bitcoin s throughput Algorand also solved the probabilistic finality oftransactions and the blockchain forks by introducing the final and tentative consensus The security and perfor mance of Algorand depend on the participation of all its nodes However they are intelligent entities and maybehave selfishly and do not cooperate to increase their benefit Like other blockchains Algorand uses rewardsto encourage nodes to participate This reward is distributed among all online nodes regardless of their role Another incentive that blockchain nodes receive is transaction fees After the block reward reaches zero thenodes are rewarded by transaction fees Also Transaction fees are necessary to encourage the nodes to validatethe transactions Therefore the amount of fee and distribution mechanism is significant for the blockchain ssecurity and growth The Algorand foundation does not pay transaction fees to nodes and stores them for thefuture This drives selfish proposers not to validate transactions and generate empty blocks To solve this prob lem we create a perfectly competitive market for Algorand block space and obtain the optimal transaction feeand block size using the variable distribution method We also provide an algorithm for optimizing Algorandconsensus protocol costs which helps it work with the least number of online nodes In addition to the amountof reward and the method of providing it the reward distribution mechanism is also important This rewardshould be shared between the participating nodes based on their role In addition to participating in the consen sus Algorand nodes are also responsible for validating messages and distributing them on the network Blocksinvolve many transactions so block validation is more expensive than other roles For this reason relay nodesmay not do their role We show that these nodes selfish behavior increases the vulnerability of Algorand toSybil attack To solve this problem we design a mechanism for identifying and punishing selfish relay nodes KeywordsTransaction Fee Block Reward Blockchain Proof of Stake Algorand Game Theory Microeconomics SybilAttack

محمد حسين منشئي

محمدرضا حيدرپور