a105ad675a
Instead of having the Group crate hold a Subgroup associated type (and thus needing to define the subgroup of a prime-order group as itself), we specify two separate sets of traits for prime-order groups and ones with a cofactor. Protocol implementors can either restrict their implementations to only work with PrimeGroup, or can explicitly choose to support CofactorGroup and then explicitly handle the subgroup edge cases with e.g. CofactorGroup::mul_by_cofactor (which would be a no-op for PrimeGroup). Protocol implementors can also choose to specialise to elliptic curves if they want to leverage an affine representation and mixed addition in their protocol for efficiency, or they can ignore those traits and stick with the simpler group-focused traits. |
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| .. | ||
| ff_derive | ||
| src | ||
| .gitignore | ||
| Cargo.toml | ||
| LICENSE-APACHE | ||
| LICENSE-MIT | ||
| README.md | ||
README.md
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.