Hierarchical interac,ons between Ethereum m sma mart contracts - - PowerPoint PPT Presentation

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Hierarchical interac,ons between Ethereum m sma mart contracts - - PowerPoint PPT Presentation

Sep 28, 2022 245 likes •604 views

Hierarchical interac,ons between Ethereum m sma mart contracts across Te Testnets Yao-Chieh Hu, Ting-Ting Lee, Dimitris Chatzopoulos, Pan Hui yhuag@ust.hk, tleeae@ust.hk, dcab@cse.ust.hk, panhui@cse.ust.hk The Hong Kong University of Science

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Hierarchical interac,ons between Ethereum m sma mart contracts across Te Testnets

Yao-Chieh Hu, Ting-Ting Lee, Dimitris Chatzopoulos, Pan Hui

yhuag@ust.hk, tleeae@ust.hk, dcab@cse.ust.hk, panhui@cse.ust.hk

The Hong Kong University of Science and Technology

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Background Knowledge

  • What is Ethereum Blockchain?

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Background Knowledge

  • What is Smart Contract?

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Background Knowledge

  • Ether(ETH) vs. Gas

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Background Knowledge

  • What is Test Networks (testnets)?

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Background Knowledge

  • What is a dApp (decentralized applicaRon)?

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Add a pic of DApp

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The Problem

  • Smart contracts cannot share common states
  • Our proposal:

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Exis,ng Alterna,ves

  • Smart Contract Inheritance
  • Share logic, not data

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Exis,ng Alterna,ves

  • Libraries
  • Share logic, not data

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Comparison with DApp

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DApps can access everything on the client contracts Custodian contracts can only access the shared state of the client contracts

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Use Case - eTickets

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Use Case

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  • Custodian Contract (movie company) creates client

contracts as Rckets

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Use Case

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  • Alice buys Rcket
  • Client contract ownership transfers from movie seller to

Alice

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Use Case

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  • Alice sells her Rcket to Bob
  • Client contract transfers Rcket ownership from Alice to

Bob

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Use Case

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  • Movie Rcket expiring Rme changed
  • Custodian contract changes the shared variable

“expireTime” in every client contract

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Technology Used

  • Ethereum Blockchain and Solidity
  • Testnets
  • Ropsten (196 nodes | PoW)
  • Rinkeby (49 nodes | PoA)
  • Kovan (145 nodes | PoA)
  • MetaMask
  • The Truffle Framework

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Experiments

  • Latency
  • Deployment
  • Shared state update
  • Gas Usage
  • Deployment
  • Shared state update

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Deployment latency

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Deployment latency per contract

Client Contract Deployment EffecRve Latency across testnets

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Deployment gas usage

Client Contract Deployment Gas Usage on Ropsten testnet

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State muta,on

Shared state mutaRon latency across Ethereum testnets

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sec

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State muta,on gas usage

Shared state mutaRon gas usage on Ropsten testnet

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Max number of clients that can be mutated at once

Maximum batch size of shared state mutaRon across testnets

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Conclusion

  • Hierarchical structure of Ethereum smart contract

can allow shared states between contracts!

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Any ques;ons? yhuag@ust.hk

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Back up Slides

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Experiments (1)

Custodian Contract Deployment Latency across Testnets

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sec

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Experiments (2)

Custodian Contract Deployment Gas Usage across testnets

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Experiments (3)

Client Contract Deployment Total Latency across testnets

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sec

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Experiments (6)

Shared state mutaRon latency across Ethereum testnets

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sec

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Experiments (7)

Shared state mutaRon average latency across Ethereum testnets

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Experiments (8)

Shared state mutaRon gas usage on Ropsten testnet

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State muta,on per contract

Shared state mutaRon average latency across Ethereum testnets

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Solu,on Breakdown - Architecture

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Architecture

  • Custodian contract
  • Supervise, track and manage Client contracts
  • Client contract
  • Only be created from its Custodian contract
  • Only shared states are externally modifiable

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