We are diversifying ourselves to apply formal verification on 3️⃣ new languages with Solidity, Rust, and TypeScript. In this article we describe our approach. For these three languages, we translate the code to the proof system 🐓 Coq. We generate the cleanest 🧼 possible output to simplify the formal verification 📐 effort that comes after.

Formal verification is a way to ensure that a program follows its specification in 💯% of cases thanks to the use of mathematical methods. It removes far more bugs and security issues than testing, and is necessary to deliver software of the highest quality 💎.

Here we recall some blog articles that we have written since this summer, on the formal verification of the protocol of Tezos. For this project, we are verifying a code base of around 100,000 lines of OCaml code. We automatically convert the OCaml code to the proof system Coq using the converter coq-of-ocaml. We then apply various proof techniques to make sure that the protocol of Tezos does not contain bugs.

In an effort to support the latest version of the protocol of Tezos we upgraded coq-of-ocaml to add compatibility with OCaml 4.14. The result is available in the branch ocaml-4.14. We describe here how we made this upgrade.

Here we give an update on our verification effort on the protocol of Tezos. We add the marks:

• ✅ for "rather done"
• 🌊 for "partially done"
• ❌ for "most is yet to do"

On the website of project, we also automatically generates pages such as Compare to follow the status of the tasks.

Our primary goal at Formal Land 🌲 is to make Tezos the first crypto-currency with a formally verified implementation. With formal verification, thanks to mathematical methods, we can check that a program behaves as expected for all possible inputs. Formal verification goes beyond what testing can do, as testing can only handle a finite amount of cases. That is critical as cryptocurrencies hold a large amount of money (around $3B for Tezos today). The current result of our verification project is available on nomadic-labs.gitlab.io/coq-tezos-of-ocaml. Formal verification is also key to allowing Tezos to evolve constantly in a safe and backward compatible manner.

Recently, we added two new blog posts about the verification of the crypto-currency Tezos:

• Verify the Michelson types of Mi-Cho-Coq to compare the types defined in the Tezos code for the Michelson interpreter and in the Mi-Cho-Coq library to verify smart contracts;
• Translate the Tenderbake's code to Coq to explain how we translated the recent changes in Tezos to the Coq using coq-of-ocaml. In particular we translated the code of the new Tenderbake consensus algorithm.

We also talked at the Lambda Lille Meetup (in French) to present our work on coq-of-ocaml for Tezos. A video on the Youtube channel of the Meetup should be available shortly. We thanks the organizers for hosting the talk.

We added a blog post about the verification of the use of data-encodings in the protocol of Tezos. Currently, we work on the verification of Tezos and publish our blog articles there. We use coq-of-ocaml to translate the OCaml code to Coq and do our verification effort.

Welcome to the blog of Formal Land. Here we will post various updates about the work we are doing.