Introduction


F* (pronounced F star) is a general-purpose functional programming language with effects aimed at program verification. It puts together the automation of an SMT-backed deductive verification tool with the expressive power of a proof assistant based on dependent types. After verification, F* programs can be extracted to efficient OCaml, F#, C or ASM code. This enables verifying the functional correctness and security of realistic applications. The main ongoing use case of F* is building a verified, drop-in replacement for the whole HTTPS stack in Project Everest. This includes verified implementations of TLS 1.2 and 1.3 and of the underlying cryptographic primitives.

F*'s type system includes dependent types, monadic effects, refinement types, and a weakest precondition calculus. Together, these features allow expressing precise and compact specifications for programs, including functional correctness and security properties. The F* type-checker aims to prove that programs meet their specifications using a combination of SMT solving and interactive proofs.

F* is written entirely in F*, and bootstraps in OCaml and F#. It is open source and under active development on GitHub. A detailed description of the current F* variant is available in a series of POPL papers (2016, 2017, and 2018). You can learn more about F* by following the online tutorial and reading our papers. Materials from recent talks are also available below. And to keep up to date with the latest news on F* you can read our blog.



Download


F* is open source, distributed under the Apache 2.0 license. It is developed in the open and the source is hosted on GitHub. Binary packages are also available for multiple platforms.

This is the easiest way to get F* quickly running on your machine, but if the binary package you use is old you might be missing out on new features and bug fixes. We also provide experimental automatic weekly builds and of course you can also build F* from source yourself.

F* Tutorial


Click the image below to start the F* tutorial.

F* Tutorial

Low* tutorial


We also have a Low* tutorial that covers Low*, a low-level subset of F*. The tutorial also explains how to use the dedicated compiler KReMLin to compile Low* to C.

Support


For documentation on F* please refer to the tutorial and the GitHub wiki.

F* is a state-of-the-art research project under active development; as such, it contains a number of known bugs. If you encounter a problem with F*, we encourage you to report it to the GitHub issue tracker. Please understand that we may not have the necessary manpower to address new feature requests - as an open source project, we welcome your contributions to help improve F*.

The fstar-club mailing list is dedicated to F* users. Here is where all F* announcements are made to the general public (e.g. for releases, new papers, etc) and where users can ask questions, ask for help, discuss, provide feedback, announce jobs requiring at least 10 years of F* experience, etc. List archives are public, but only members can post. Join here!

People


F* is a joint project between Microsoft Research, INRIA, and the community at large.

Current team


Past contributors


Papers


18 results
2019
[18] Meta-F*: Proof Automation with SMT, Tactics, and Metaprograms (, , , , , , , , , , , , ), In 28th European Symposium on Programming (ESOP), . (To appear) [bibtex] [pdf]
[17] Dijkstra Monads for All (, , , , , , ), arXiv:1903.01237, . [bibtex] [pdf]
[16] A Verified, Efficient Embedding of a Verifiable Assembly Language (, , , , , ), In PACMPL, . [bibtex] [pdf]
2018
[15] Recalling a Witness: Foundations and Applications of Monotonic State (, , , , , ), In PACMPL, volume 2, . [bibtex] [pdf]
[14] A Monadic Framework for Relational Verification: Applied to Information Security, Program Equivalence, and Optimizations (, , , , , , , , , ), In The 7th ACM SIGPLAN International Conference on Certified Programs and Proofs, . [bibtex] [pdf]
2017
[13] Verified Low-Level Programming Embedded in F* (, , , , , , , , , , ), In PACMPL, volume 1, . [bibtex] [pdf] [doi]
[12] Everest: Towards a Verified, Drop-in Replacement of HTTPS (, , , , , , , , , , , , , , , , , , , , , ), In 2nd Summit on Advances in Programming Languages, . [bibtex] [pdf]
[11] Dijkstra Monads for Free (, , , , , , , ), In 44th ACM SIGPLAN Symposium on Principles of Programming Languages (POPL), ACM, . [bibtex] [pdf] [doi]
2016
[10] Towards a Provably Correct Encoding from F* to SMT (), Inria Internship Report, . [bibtex] [pdf]
[9] Dependent Types and Multi-Monadic Effects in F* (, , , , , , , , , , , ), In 43rd ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages (POPL), ACM, . [bibtex] [pdf]
2015
[8] Wys*: A Verified Language Extension for Secure Multi-party Computations (, , ), . [bibtex] [pdf]
2014
[7] Gradual typing embedded securely in JavaScript (, , , , , , ), In The 41st Annual ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages (Suresh Jagannathan, Peter Sewell, eds.), ACM, . [bibtex] [pdf] [doi]
[6] Probabilistic relational verification for cryptographic implementations (, , , , , ), In The 41st Annual ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages (Suresh Jagannathan, Peter Sewell, eds.), ACM, . [bibtex] [pdf] [doi]
2013
[5] Fully Abstract Compilation to JavaScript (, , , , , ), In 40th ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages, . [bibtex] [pdf]
[4] Verifying Higher-order Programs with the Dijkstra Monad (, , , , ), In Proceedings of the 34th annual ACM SIGPLAN conference on Programming Language Design and Implementation, . [bibtex] [pdf]
[3] Secure distributed programming with value-dependent types (, , , , , ), In J. Funct. Program., volume 23, . [bibtex] [pdf]
2012
[2] Self-Certification: Bootstrapping Certified Typecheckers in F* with Coq (, , , ), In Proceedings of the 39th ACM SIGPLAN-SIGACT Symposium on Principles of Programming Languages, . [bibtex] [pdf]
2011
[1] Secure distributed programming with value-dependent types (, , , , , ), In Proceeding of the 16th ACM SIGPLAN international conference on Functional Programming (Manuel M. T. Chakravarty, Zhenjiang Hu, Olivier Danvy, eds.), ACM, . [bibtex] [pdf] [doi]

Talks