68 lines
1.8 KiB
Markdown
68 lines
1.8 KiB
Markdown
# ff
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`ff` is a finite field library written in pure Rust, with no `unsafe{}` code.
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## Disclaimers
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* This library does not provide constant-time guarantees.
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## Usage
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Add the `ff` crate to your `Cargo.toml`:
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```toml
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[dependencies]
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ff = "0.5"
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```
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The `ff` crate contains `Field`, `PrimeField`, `PrimeFieldRepr` and `SqrtField` traits.
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See the **[documentation](https://docs.rs/ff/)** for more.
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### #![derive(PrimeField)]
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If you need an implementation of a prime field, this library also provides a procedural
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macro that will expand into an efficient implementation of a prime field when supplied
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with the modulus. `PrimeFieldGenerator` must be an element of Fp of p-1 order, that is
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also quadratic nonresidue.
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First, enable the `derive` crate feature:
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```toml
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[dependencies]
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ff = { version = "0.4", features = ["derive"] }
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```
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And then use the macro like so:
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```rust
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extern crate rand;
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#[macro_use]
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extern crate ff;
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#[derive(PrimeField)]
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#[PrimeFieldModulus = "52435875175126190479447740508185965837690552500527637822603658699938581184513"]
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#[PrimeFieldGenerator = "7"]
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struct Fp(FpRepr);
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```
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And that's it! `Fp` now implements `Field` and `PrimeField`. `Fp` will also implement
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`SqrtField` if supported. The library implements `FpRepr` itself and derives
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`PrimeFieldRepr` for it.
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## License
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Licensed under either of
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* Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
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http://www.apache.org/licenses/LICENSE-2.0)
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* MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
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at your option.
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### Contribution
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Unless you explicitly state otherwise, any contribution intentionally
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submitted for inclusion in the work by you, as defined in the Apache-2.0
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license, shall be dual licensed as above, without any additional terms or
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conditions.
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