pirate-librustzcash/ff
Jack Grigg 15e229509a ff: Move pow_vartime back into Field trait
The only places we don't use constant u64 limbs, we use PrimeField::char
instead (except in a single test where we use a field element).
2020-05-02 18:54:02 +12:00
..
ff_derive ff: Add PrimeField::ReprEndianness associated type 2020-05-02 18:54:02 +12:00
src ff: Move pow_vartime back into Field trait 2020-05-02 18:54:02 +12:00
.gitignore Add 'ff/' from commit '661558e0c8a5e02e08dac6530d39b2e38919aa04' 2019-01-06 09:37:22 +00:00
Cargo.toml ff: Add PrimeField::ReprEndianness associated type 2020-05-02 18:54:02 +12:00
LICENSE-APACHE Add 'ff/' from commit '661558e0c8a5e02e08dac6530d39b2e38919aa04' 2019-01-06 09:37:22 +00:00
LICENSE-MIT Add 'ff/' from commit '661558e0c8a5e02e08dac6530d39b2e38919aa04' 2019-01-06 09:37:22 +00:00
README.md Merge commit 'd7f78db121ee6f720e97401ded0c9c597d1a4857' into depends-updates-2 2020-03-03 17:44:28 -07:00

ff

ff is a finite field library written in pure Rust, with no unsafe{} code.

Disclaimers

  • This library does not provide constant-time guarantees.

Usage

Add the ff crate to your Cargo.toml:

[dependencies]
ff = "0.5"

The ff crate contains Field, PrimeField, PrimeFieldRepr and SqrtField traits. See the documentation 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:

[dependencies]
ff = { version = "0.4", features = ["derive"] }

And then use the macro like so:

extern crate rand;
#[macro_use]
extern crate ff;

#[derive(PrimeField)]
#[PrimeFieldModulus = "52435875175126190479447740508185965837690552500527637822603658699938581184513"]
#[PrimeFieldGenerator = "7"]
struct Fp(FpRepr);

And that's it! Fp now implements Field and PrimeField. Fp will also implement SqrtField if supported. The library implements FpRepr itself and derives PrimeFieldRepr for it.

License

Licensed under either of

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.