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Extracting smart contracts tested and verified in Coq

Research output: Contribution to book/anthology/report/proceedingArticle in proceedingsResearchpeer-review


  • Danil Annenkov, Concordium Blockchain Research Center
  • ,
  • Mikkel Milo
  • ,
  • Jakob Botsch Nielsen, Concordium Blockchain Research Center
  • ,
  • Bas Spitters

We implement extraction of Coq programs to functional languages based on MetaCoq's certified erasure. As part of this, we implement an optimisation pass removing unused arguments. We prove the pass correct wrt. a conventional call-by-value operational semantics of functional languages. We apply this to two functional smart contract languages, Liquidity and Midlang, and to the functional language Elm. Our development is done in the context of the ConCert framework that enables smart contract verification. We contribute a verified boardroom voting smart contract featuring maximum voter privacy such that each vote is kept private except under collusion of all other parties. We also integrate property-based testing into ConCert using QuickChick and our development is the first to support testing properties of interacting smart contracts. We test several complex contracts such as a DAO-like contract, an escrow contract, an implementation of a Decentralized Finance (DeFi) contract which includes a custom token standard (Tezos FA2), and more. In total, this gives us a way to write dependent programs in Coq, test them semi-automatically, verify, and then extract to functional smart contract languages, while retaining a small trusted computing base of only MetaCoq and the pretty-printers into these languages.

Original languageEnglish
Title of host publicationCPP 2021 - Proceedings of the 10th ACM SIGPLAN International Conference on Certified Programs and Proofs, co-located with POPL 2021
EditorsCatalin Hritcu, Andrei Popescu
Number of pages17
PublisherAssociation for Computing Machinery
Publication yearJan 2021
ISBN (Electronic)9781450382991
Publication statusPublished - Jan 2021
Event10th ACM SIGPLAN International Conference on Certified Programs and Proofs, CPP 2021, co-located with POPL 2021 - Virtual, Online, Denmark
Duration: 17 Jan 202119 Jan 2021


Conference10th ACM SIGPLAN International Conference on Certified Programs and Proofs, CPP 2021, co-located with POPL 2021
ByVirtual, Online

    Research areas

  • Blockchain, Certified programming, Code extraction, Coq, Formal verification, Proof assistants, Property-based testing, Smart contracts, Software correctness

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