1761ebfb35
The sqrt() function is now part of the Field trait. ff_derive returns an error on fields for which it does not support generating a square root function. Note that Fq6 and Fq12 in pairing::bls12_381 leave the function unimplemented. They will be dropped once the migration to the bls12_381 crate is complete. The equivalent structs in that crate are not exposed.
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
- Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
- MIT license (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.