Files
pirate-librustzcash/pairing/src/lib.rs
2019-01-06 09:50:07 +00:00

118 lines
3.8 KiB
Rust

// `clippy` is a code linting tool for improving code quality by catching
// common mistakes or strange code patterns. If the `cargo-clippy` feature
// is provided, all compiler warnings are prohibited.
#![cfg_attr(feature = "cargo-clippy", deny(warnings))]
#![cfg_attr(feature = "cargo-clippy", allow(inline_always))]
#![cfg_attr(feature = "cargo-clippy", allow(too_many_arguments))]
#![cfg_attr(feature = "cargo-clippy", allow(unreadable_literal))]
#![cfg_attr(feature = "cargo-clippy", allow(many_single_char_names))]
#![cfg_attr(feature = "cargo-clippy", allow(new_without_default_derive))]
#![cfg_attr(feature = "cargo-clippy", allow(write_literal))]
// Force public structures to implement Debug
#![deny(missing_debug_implementations)]
extern crate byteorder;
extern crate ff;
extern crate group;
extern crate rand;
#[cfg(test)]
pub mod tests;
pub mod bls12_381;
use ff::{Field, PrimeField, ScalarEngine, SqrtField};
use group::{CurveAffine, CurveProjective};
/// An "engine" is a collection of types (fields, elliptic curve groups, etc.)
/// with well-defined relationships. In particular, the G1/G2 curve groups are
/// of prime order `r`, and are equipped with a bilinear pairing function.
pub trait Engine: ScalarEngine {
/// The projective representation of an element in G1.
type G1: CurveProjective<
Engine = Self,
Base = Self::Fq,
Scalar = Self::Fr,
Affine = Self::G1Affine,
>
+ From<Self::G1Affine>;
/// The affine representation of an element in G1.
type G1Affine: PairingCurveAffine<
Engine = Self,
Base = Self::Fq,
Scalar = Self::Fr,
Projective = Self::G1,
Pair = Self::G2Affine,
PairingResult = Self::Fqk,
>
+ From<Self::G1>;
/// The projective representation of an element in G2.
type G2: CurveProjective<
Engine = Self,
Base = Self::Fqe,
Scalar = Self::Fr,
Affine = Self::G2Affine,
>
+ From<Self::G2Affine>;
/// The affine representation of an element in G2.
type G2Affine: PairingCurveAffine<
Engine = Self,
Base = Self::Fqe,
Scalar = Self::Fr,
Projective = Self::G2,
Pair = Self::G1Affine,
PairingResult = Self::Fqk,
>
+ From<Self::G2>;
/// The base field that hosts G1.
type Fq: PrimeField + SqrtField;
/// The extension field that hosts G2.
type Fqe: SqrtField;
/// The extension field that hosts the target group of the pairing.
type Fqk: Field;
/// Perform a miller loop with some number of (G1, G2) pairs.
fn miller_loop<'a, I>(i: I) -> Self::Fqk
where
I: IntoIterator<
Item = &'a (
&'a <Self::G1Affine as PairingCurveAffine>::Prepared,
&'a <Self::G2Affine as PairingCurveAffine>::Prepared,
),
>;
/// Perform final exponentiation of the result of a miller loop.
fn final_exponentiation(&Self::Fqk) -> Option<Self::Fqk>;
/// Performs a complete pairing operation `(p, q)`.
fn pairing<G1, G2>(p: G1, q: G2) -> Self::Fqk
where
G1: Into<Self::G1Affine>,
G2: Into<Self::G2Affine>,
{
Self::final_exponentiation(&Self::miller_loop(
[(&(p.into().prepare()), &(q.into().prepare()))].into_iter(),
)).unwrap()
}
}
/// Affine representation of an elliptic curve point that can be used
/// to perform pairings.
pub trait PairingCurveAffine: CurveAffine {
type Prepared: Clone + Send + Sync + 'static;
type Pair: PairingCurveAffine<Pair = Self>;
type PairingResult: Field;
/// Prepares this element for pairing purposes.
fn prepare(&self) -> Self::Prepared;
/// Perform a pairing
fn pairing_with(&self, other: &Self::Pair) -> Self::PairingResult;
}