Formal Verification for Smart Contracts

Formal verification of smart contracts is done by expressing the logic and desired behavior of the smart contract as mathematical statements. Auditors then can use automated tools to verify that these statements are correct.

The process includes:

  • Define contract specifications and desired characteristics in a formal language.
  • Convert contract code into formal representations such as mathematical models and logic.
  • Validate that contract specifications and properties are correct using an automated theorem prover or model checker.
  • Repeat the validation process to find and fix any errors or deviations from the desired properties.

In some cases, an automated theorem prover or model checker cannot prove or disprove that a property is true. It is then necessary to refine the specification and desired characteristics and repeat the formal method.

Specifications and desired properties can be refined by applying more specifications to smaller pieces of code or by making the specifications more detailed. This makes it easier for theorem provers and model checkers to verify that the specifications and properties are correct.

Formal review can be applied to a single contract or to multiple contracts simultaneously. Web3 projects often are built with and depend on multiple contracts, so it is important to ensure that the contracts work together and correctly implement the desired project functionality.

This use of mathematical reasoning helps ensure that formally verified smart contracts are free of errors, vulnerabilities, and other unintended behavior. It also helps build confidence in the contract as its veracity has been rigorously proven.