# ff `ff` is a finite field library written in pure Rust, with no `unsafe{}` code. ## Disclaimers * This library does not provide constant-time guarantees. The traits enable downstream users to expose constant-time logic, but `#[derive(PrimeField)]` in particular does not generate constant-time code (even for trait methods that return constant-time-compatible values). ## Usage Add the `ff` crate to your `Cargo.toml`: ```toml [dependencies] ff = "0.13" ``` The `ff` crate contains the `Field` and `PrimeField` traits. See the **[documentation](https://docs.rs/ff/)** for more. ### #![derive(PrimeField)] If you need an implementation of a prime field, this library also provides a procedural macro that will expand into an efficient implementation of a prime field when supplied with the modulus. `PrimeFieldGenerator` must be an element of Fp of p-1 order, that is also quadratic nonresidue. First, enable the `derive` crate feature: ```toml [dependencies] ff = { version = "0.13", features = ["derive"] } ``` And then use the macro like so: ```rust #[macro_use] extern crate ff; #[derive(PrimeField)] #[PrimeFieldModulus = "52435875175126190479447740508185965837690552500527637822603658699938581184513"] #[PrimeFieldGenerator = "7"] #[PrimeFieldReprEndianness = "little"] struct Fp([u64; 4]); ``` And that's it! `Fp` now implements `Field` and `PrimeField`. ## Minimum Supported Rust Version Requires Rust **1.56** or higher. Minimum supported Rust version can be changed in the future, but it will be done with a minor version bump. ## License Licensed under either of * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0) * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT) at your option. ### Contribution Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.