Mi-Cho-Coq, a Framework for Certifying Tezos Smart Contracts

Bernardo, Bruno; Cauderlier, Raphaël; Hu, Zhenlei; Pesin, Basile; Tesson, Julien

doi:10.1007/978-3-030-54994-7_28

Cited by 31 publications

(33 citation statements)

References 13 publications

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“…Based on the generated definition, he verifies several properties of Ethereum smart contracts using Isabelle/HOL. Bernardo et al [2] implemented Mi-Cho-Coq, a formalization of the semantics of Michelson using the Coq proof assistant. They also verified several Michelson contracts.…”

Section: Related Workmentioning

confidence: 99%

“…We show that our tool can verify several practical smart contracts. In addition to the contracts we wrote ourselves, we apply our tool to the sample Michelson programs used in Mi-cho-coq [2], a formalization of Michelson in Coq proof assistant [21]. These contracts consist of practical contracts such as one that checks a digital signature and one that transfers money.…”

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confidence: 99%

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Helmholtz: A Verifier for Tezos Smart Contracts Based on Refinement Types

Nishida

Saito

Chen

et al. 2021

Lecture Notes in Computer Science

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A smart contract is a program executed on a blockchain, based on which many cryptocurrencies are implemented, and is being used for automating transactions. Due to the large amount of money that smart contracts deal with, there is a surging demand for a method that can statically and formally verify them.This tool paper describes our type-based static verification tool Helmholtz for Michelson, which is a statically typed stack-based language for writing smart contracts that are executed on the blockchain platform Tezos. Helmholtz is designed on top of our extension of Michelson’s type system with refinement types. Helmholtz takes a Michelson program annotated with a user-defined specification written in the form of a refinement type as input; it then typechecks the program against the specification based on the refinement type system, discharging the generated verification conditions with the SMT solver Z3. We briefly introduce our refinement type system for the core calculus Mini-Michelson of Michelson, which incorporates the characteristic features such as compound datatypes (e.g., lists and pairs), higher-order functions, and invocation of another contract. Helmholtz successfully verifies several practical Michelson programs, including one that transfers money to an account and that checks a digital signature.

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Section: Related Workmentioning

confidence: 99%

mentioning

confidence: 99%

Helmholtz: A Verifier for Tezos Smart Contracts Based on Refinement Types

Nishida

Saito

Chen

et al. 2021

Lecture Notes in Computer Science

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show abstract

“…However, this approach lacks the integration of verification features. On the verification side, Tezos blockchain [3] has already considered formal verification problems during the protocol design phase and code implementation. Properties are extracted from virtual machine code and fed to a theorem prover like Coq [4].…”

Section: Related Workmentioning

confidence: 99%

Model-driven approach for the design of Multi-Chain Smart Contracts

Barisic

Zhu

Mallet

2021

2021 3rd Conference on Blockchain Research &Amp; Applications for Innovative Networks and Services (BRAINS)

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“…It is an accounts-based proof-of-stake blockchain system with the unique feature that it is a universal blockchain in the sense that the protocol for running Tezos is itself data on the Tezos blockchain, and this data is subject to regular upgrade by stake-weighted community vote. 2 Universality favours a healthy modularity at every level of the system's design, since almost anything in the running system can be and is subject to update. Tezos has just one native token: the tez.…”

Section: Tezos: a Universal Modular Blockchainmentioning

confidence: 99%

Money grows on (proof-)trees: the formal FA1.2 ledger standard

Gabbay,

Jakobsson,

Sojakova

2021

Preprint

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Once you have invented digital money, you may need a ledger to track who owns what -along with an interface to that ledger so that users of your money can transact. On the Tezos blockchain this implies: a smart contract (distributed program), storing in its state a ledger to map owner addresses to token quantities; along with standardised entrypoints to query and transact on accounts.A bank does a similar job -it maps account numbers to account quantities and permits users to transact -but in return the bank demands trust, it incurs expense to maintain a centralised server and staff, it uses a proprietary interface . . . and it may speculate using your money and/or display rent-seeking behaviour. A blockchain ledger is by design decentralised, inexpensive, open, and it won't just decide to bet your tokens on risky derivatives (unless you want it to). The FA1.2 standard is an open standard for ledger-keeping smart contracts on the Tezos blockchain. Several FA1.2 implementations already exist.Or do they? Is the standard sensible and complete? Are the implementations correct? And what are they implementations of ? The FA1.2 standard is written in English, a specification language favoured by wet human brains but notorious for its incompleteness and ambiguity when rendered into dry and unforgiving code.In this paper we report on a formalisation of the FA1.2 standard as a Coq specification, and on a formal verification of three FA1.2-compliant smart contracts with respect to that specification. Errors were found and ambiguities were resolved; but also, there now exists a mathematically precise and battle-tested specification of the FA1.2 ledger standard.We will describe FA1.2 itself, outline the structure of the Coq theories -which in itself captures some non-trivial and novel design decisions of the development -and review the detailed verification of the implementations. ACM Subject ClassificationSoftware and its engineering → Formal software verification; Theory of computation → Program verification; Social and professional topics → Quality assurance Keywords and phrases Distributed ledger, smart contracts, Coq, formal verification, blockchain Digital Object Identifier 10.4230/OASIcs.FMBC.2021. AcknowledgementsThe authors acknowledge the support of Nomadic Labs and the detailed and very helpful comments of three anonymous referees. We also thank Benoît Rognier, the Edukera team, and Tom Jack for their feedback and support.

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Mi-Cho-Coq, a Framework for Certifying Tezos Smart Contracts

Cited by 31 publications

References 13 publications

Helmholtz: A Verifier for Tezos Smart Contracts Based on Refinement Types

Helmholtz: A Verifier for Tezos Smart Contracts Based on Refinement Types

Model-driven approach for the design of Multi-Chain Smart Contracts

Money grows on (proof-)trees: the formal FA1.2 ledger standard

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