Elliptic curves utilities refactory (#2068)

- Usage the new published
[arkworks-extensions](https://github.com/paritytech/arkworks-extensions)
crates.
  Hooks are internally defined to jump into the proper host functions.
- Conditional compilation of each curve (gated by feature with curve
name)
- Separation in smaller host functions sets, divided by curve (fits
nicely with prev point)

substrate/primitives/crypto/ec-utils/src/bw6_761.rs

@@ -0,0 +1,186 @@
+// This file is part of Substrate.
+
+// Copyright (C) Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! *BW6-761* types and host functions.
+
+use crate::utils;
+use ark_bw6_761_ext::CurveHooks;
+use ark_ec::{pairing::Pairing, CurveConfig};
+use sp_runtime_interface::runtime_interface;
+use sp_std::vec::Vec;
+
+/// First pairing group definitions.
+pub mod g1 {
+	pub use ark_bw6_761_ext::g1::{G1_GENERATOR_X, G1_GENERATOR_Y};
+	/// Group configuration.
+	pub type Config = ark_bw6_761_ext::g1::Config<super::HostHooks>;
+	/// Short Weierstrass form point affine representation.
+	pub type G1Affine = ark_bw6_761_ext::g1::G1Affine<super::HostHooks>;
+	/// Short Weierstrass form point projective representation.
+	pub type G1Projective = ark_bw6_761_ext::g1::G1Projective<super::HostHooks>;
+}
+
+/// Second pairing group definitions.
+pub mod g2 {
+	pub use ark_bw6_761_ext::g2::{G2_GENERATOR_X, G2_GENERATOR_Y};
+	/// Group configuration.
+	pub type Config = ark_bw6_761_ext::g2::Config<super::HostHooks>;
+	/// Short Weierstrass form point affine representation.
+	pub type G2Affine = ark_bw6_761_ext::g2::G2Affine<super::HostHooks>;
+	/// Short Weierstrass form point projective representation.
+	pub type G2Projective = ark_bw6_761_ext::g2::G2Projective<super::HostHooks>;
+}
+
+pub use self::{
+	g1::{Config as G1Config, G1Affine, G1Projective},
+	g2::{Config as G2Config, G2Affine, G2Projective},
+};
+
+/// Curve hooks jumping into [`host_calls`] host functions.
+#[derive(Copy, Clone)]
+pub struct HostHooks;
+
+/// Configuration for *BW6-361* curve.
+pub type Config = ark_bw6_761_ext::Config<HostHooks>;
+
+/// *BW6-361* definition.
+///
+/// A generic *BW6* model specialized with *BW6-761* configuration.
+pub type BW6_761 = ark_bw6_761_ext::BW6_761<HostHooks>;
+
+impl CurveHooks for HostHooks {
+	fn bw6_761_multi_miller_loop(
+		g1: impl Iterator<Item = <BW6_761 as Pairing>::G1Prepared>,
+		g2: impl Iterator<Item = <BW6_761 as Pairing>::G2Prepared>,
+	) -> Result<<BW6_761 as Pairing>::TargetField, ()> {
+		let g1 = utils::encode(g1.collect::<Vec<_>>());
+		let g2 = utils::encode(g2.collect::<Vec<_>>());
+		let res = host_calls::bw6_761_multi_miller_loop(g1, g2).unwrap_or_default();
+		utils::decode(res)
+	}
+
+	fn bw6_761_final_exponentiation(
+		target: <BW6_761 as Pairing>::TargetField,
+	) -> Result<<BW6_761 as Pairing>::TargetField, ()> {
+		let target = utils::encode(target);
+		let res = host_calls::bw6_761_final_exponentiation(target).unwrap_or_default();
+		utils::decode(res)
+	}
+
+	fn bw6_761_msm_g1(
+		bases: &[G1Affine],
+		scalars: &[<G1Config as CurveConfig>::ScalarField],
+	) -> Result<G1Projective, ()> {
+		let bases = utils::encode(bases);
+		let scalars = utils::encode(scalars);
+		let res = host_calls::bw6_761_msm_g1(bases, scalars).unwrap_or_default();
+		utils::decode_proj_sw(res)
+	}
+
+	fn bw6_761_msm_g2(
+		bases: &[G2Affine],
+		scalars: &[<G2Config as CurveConfig>::ScalarField],
+	) -> Result<G2Projective, ()> {
+		let bases = utils::encode(bases);
+		let scalars = utils::encode(scalars);
+		let res = host_calls::bw6_761_msm_g2(bases, scalars).unwrap_or_default();
+		utils::decode_proj_sw(res)
+	}
+
+	fn bw6_761_mul_projective_g1(base: &G1Projective, scalar: &[u64]) -> Result<G1Projective, ()> {
+		let base = utils::encode_proj_sw(base);
+		let scalar = utils::encode(scalar);
+		let res = host_calls::bw6_761_mul_projective_g1(base, scalar).unwrap_or_default();
+		utils::decode_proj_sw(res)
+	}
+
+	fn bw6_761_mul_projective_g2(base: &G2Projective, scalar: &[u64]) -> Result<G2Projective, ()> {
+		let base = utils::encode_proj_sw(base);
+		let scalar = utils::encode(scalar);
+		let res = host_calls::bw6_761_mul_projective_g2(base, scalar).unwrap_or_default();
+		utils::decode_proj_sw(res)
+	}
+}
+
+/// Interfaces for working with *Arkworks* *BW6-761* elliptic curve related types
+/// from within the runtime.
+///
+/// All types are (de-)serialized through the wrapper types from the `ark-scale` trait,
+/// with `ark_scale::{ArkScale, ArkScaleProjective}`.
+///
+/// `ArkScale`'s `Usage` generic parameter is expected to be set to "not-validated"
+/// and "not-compressed".
+#[runtime_interface]
+pub trait HostCalls {
+	/// Pairing multi Miller loop for *BW6-761*.
+	///
+	/// - Receives encoded:
+	///   - `a: ArkScale<Vec<G1Affine>>`.
+	///   - `b: ArkScale<Vec<G2Affine>>`.
+	/// - Returns encoded: `ArkScale<BW6_761;:TargetField>`.
+	fn bw6_761_multi_miller_loop(a: Vec<u8>, b: Vec<u8>) -> Result<Vec<u8>, ()> {
+		utils::multi_miller_loop::<ark_bw6_761::BW6_761>(a, b)
+	}
+
+	/// Pairing final exponentiation for *BW6-761*.
+	///
+	/// - Receives encoded: `ArkScale<BW6_761::TargetField>`.
+	/// - Returns encoded: `ArkScale<BW6_761::TargetField>`.
+	fn bw6_761_final_exponentiation(f: Vec<u8>) -> Result<Vec<u8>, ()> {
+		utils::final_exponentiation::<ark_bw6_761::BW6_761>(f)
+	}
+
+	/// Multi scalar multiplication on *G1* for *BW6-761*.
+	///
+	/// - Receives encoded:
+	///   - `bases`: `ArkScale<Vec<G1Affine>>`.
+	///   - `scalars`: `ArkScale<G1Config::ScalarField>`.
+	/// - Returns encoded: `ArkScaleProjective<G1Projective>`.
+	fn bw6_761_msm_g1(bases: Vec<u8>, scalars: Vec<u8>) -> Result<Vec<u8>, ()> {
+		utils::msm_sw::<ark_bw6_761::g1::Config>(bases, scalars)
+	}
+
+	/// Multi scalar multiplication on *G2* for *BW6-761*.
+	///
+	/// - Receives encoded:
+	///   - `bases`: `ArkScale<Vec<G2Affine>>`.
+	///   - `scalars`: `ArkScale<Vec<G2Config::ScalarField>>`.
+	/// - Returns encoded: `ArkScaleProjective<G2Projective>`.
+	fn bw6_761_msm_g2(bases: Vec<u8>, scalars: Vec<u8>) -> Result<Vec<u8>, ()> {
+		utils::msm_sw::<ark_bw6_761::g2::Config>(bases, scalars)
+	}
+
+	/// Projective multiplication on *G1* for *BW6-761*.
+	///
+	/// - Receives encoded:
+	///   - `base`: `ArkScaleProjective<G1Projective>`.
+	///   - `scalar`: `ArkScale<Vec<u64>>`.
+	/// - Returns encoded: `ArkScaleProjective<G1Projective>`.
+	fn bw6_761_mul_projective_g1(base: Vec<u8>, scalar: Vec<u8>) -> Result<Vec<u8>, ()> {
+		utils::mul_projective_sw::<ark_bw6_761::g1::Config>(base, scalar)
+	}
+
+	/// Projective multiplication on *G2* for *BW6-761*.
+	///
+	/// - Receives encoded:
+	///   - `base`: `ArkScaleProjective<G2Projective>`.
+	///   - `scalar`: `ArkScale<Vec<u64>>`.
+	/// - Returns encoded: `ArkScaleProjective<G2Projective>`.
+	fn bw6_761_mul_projective_g2(base: Vec<u8>, scalar: Vec<u8>) -> Result<Vec<u8>, ()> {
+		utils::mul_projective_sw::<ark_bw6_761::g2::Config>(base, scalar)
+	}
+}