Removes CurveAffineExt (privacy-scaling-explorations#67)

remove `CurveAffineExt`

src/arithmetic.rs

@@ -17,24 +17,6 @@ pub trait CurveEndo: CurveExt {
  fn decompose_scalar(e: &Self::ScalarExt) -> (u128, bool, u128, bool);
 }
 
-pub trait CurveAffineExt: pasta_curves::arithmetic::CurveAffine {
- fn batch_add<const COMPLETE: bool, const LOAD_POINTS: bool>(
- points: &mut [Self],
- output_indices: &[u32],
- num_points: usize,
- offset: usize,
- bases: &[Self],
- base_positions: &[u32],
- );
-
- /// Unlike the `Coordinates` trait, this just returns the raw affine coordinates without checking `is_on_curve`
- fn into_coordinates(self) -> (Self::Base, Self::Base) {
- // fallback implementation
- let coordinates = self.coordinates().unwrap();
- (*coordinates.x(), *coordinates.y())
- }
-}
-
 /// Compute a + b + carry, returning the result and the new carry over.
 #[inline(always)]
 pub(crate) const fn adc(a: u64, b: u64, carry: u64) -> (u64, u64) {

src/bn256/curve.rs

@@ -12,11 +12,11 @@ use crate::group::Curve;
 use crate::group::{cofactor::CofactorGroup, prime::PrimeCurveAffine, Group, GroupEncoding};
 use crate::hash_to_curve::svdw_hash_to_curve;
 use crate::{
- batch_add, impl_add_binop_specify_output, impl_binops_additive,
- impl_binops_additive_specify_output, impl_binops_multiplicative,
- impl_binops_multiplicative_mixed, impl_sub_binop_specify_output, new_curve_impl,
+ impl_add_binop_specify_output, impl_binops_additive, impl_binops_additive_specify_output,
+ impl_binops_multiplicative, impl_binops_multiplicative_mixed, impl_sub_binop_specify_output,
+ new_curve_impl,
 };
-use crate::{Coordinates, CurveAffine, CurveAffineExt, CurveExt};
+use crate::{Coordinates, CurveAffine, CurveExt};
 use core::cmp;
 use core::fmt::Debug;
 use core::iter::Sum;
@@ -56,22 +56,6 @@ new_curve_impl!(
  |_, _| unimplemented!(),
 );
 
-impl CurveAffineExt for G1Affine {
- batch_add!();
-
- fn into_coordinates(self) -> (Self::Base, Self::Base) {
- (self.x, self.y)
- }
-}
-
-impl CurveAffineExt for G2Affine {
- batch_add!();
-
- fn into_coordinates(self) -> (Self::Base, Self::Base) {
- (self.x, self.y)
- }
-}
-
 const G1_GENERATOR_X: Fq = Fq::one();
 const G1_GENERATOR_Y: Fq = Fq::from_raw([2, 0, 0, 0]);
 const G1_A: Fq = Fq::from_raw([0, 0, 0, 0]);

src/derive/curve.rs

@@ -1,145 +1,3 @@
-#[macro_export]
-macro_rules! batch_add {
- () => {
- fn batch_add<const COMPLETE: bool, const LOAD_POINTS: bool>(
- points: &mut [Self],
- output_indices: &[u32],
- num_points: usize,
- offset: usize,
- bases: &[Self],
- base_positions: &[u32],
- ) {
- // assert!(Self::constant_a().is_zero());
-
- let get_point = |point_data: u32| -> Self {
- let negate = point_data & 0x80000000 != 0;
- let base_idx = (point_data & 0x7FFFFFFF) as usize;
- if negate {
- bases[base_idx].neg()
- } else {
- bases[base_idx]
- }
- };
-
- // Affine addition formula (P != Q):
- // - lambda = (y_2 - y_1) / (x_2 - x_1)
- // - x_3 = lambda^2 - (x_2 + x_1)
- // - y_3 = lambda * (x_1 - x_3) - y_1
-
- // Batch invert accumulator
- let mut acc = Self::Base::one();
-
- for i in (0..num_points).step_by(2) {
- // Where that result of the point addition will be stored
- let out_idx = output_indices[i >> 1] as usize - offset;
-
- #[cfg(all(feature = "prefetch", target_arch = "x86_64"))]
- if i < num_points - 2 {
- if LOAD_POINTS {
- $crate::prefetch::<Self>(bases, base_positions[i + 2] as usize);
- $crate::prefetch::<Self>(bases, base_positions[i + 3] as usize);
- }
- $crate::prefetch::<Self>(
- points,
- output_indices[(i >> 1) + 1] as usize - offset,
- );
- }
- if LOAD_POINTS {
- points[i] = get_point(base_positions[i]);
- points[i + 1] = get_point(base_positions[i + 1]);
- }
-
- if COMPLETE {
- // Nothing to do here if one of the points is zero
- if (points[i].is_identity() | points[i + 1].is_identity()).into() {
- continue;
- }
-
- if points[i].x == points[i + 1].x {
- if points[i].y == points[i + 1].y {
- // Point doubling (P == Q)
- // - s = (3 * x^2) / (2 * y)
- // - x_2 = s^2 - (2 * x)
- // - y_2 = s * (x - x_2) - y
-
- // (2 * x)
- points[out_idx].x = points[i].x + points[i].x;
- // x^2
- let xx = points[i].x.square();
- // (2 * y)
- points[i + 1].x = points[i].y + points[i].y;
- // (3 * x^2) * acc
- points[i + 1].y = (xx + xx + xx) * acc;
- // acc * (2 * y)
- acc *= points[i + 1].x;
- continue;
- } else {
- // Zero
- points[i] = Self::identity();
- points[i + 1] = Self::identity();
- continue;
- }
- }
- }
-
- // (x_2 + x_1)
- points[out_idx].x = points[i].x + points[i + 1].x;
- // (x_2 - x_1)
- points[i + 1].x -= points[i].x;
- // (y2 - y1) * acc
- points[i + 1].y = (points[i + 1].y - points[i].y) * acc;
- // acc * (x_2 - x_1)
- acc *= points[i + 1].x;
- }
-
- // Batch invert
- if COMPLETE {
- if (!acc.is_zero()).into() {
- acc = acc.invert().unwrap();
- }
- } else {
- acc = acc.invert().unwrap();
- }
-
- for i in (0..num_points).step_by(2).rev() {
- // Where that result of the point addition will be stored
- let out_idx = output_indices[i >> 1] as usize - offset;
-
- #[cfg(all(feature = "prefetch", target_arch = "x86_64"))]
- if i > 0 {
- $crate::prefetch::<Self>(
- points,
- output_indices[(i >> 1) - 1] as usize - offset,
- );
- }
-
- if COMPLETE {
- // points[i] is zero so the sum is points[i + 1]
- if points[i].is_identity().into() {
- points[out_idx] = points[i + 1];
- continue;
- }
- // points[i + 1] is zero so the sum is points[i]
- if points[i + 1].is_identity().into() {
- points[out_idx] = points[i];
- continue;
- }
- }
-
- // lambda
- points[i + 1].y *= acc;
- // acc * (x_2 - x_1)
- acc *= points[i + 1].x;
- // x_3 = lambda^2 - (x_2 + x_1)
- points[out_idx].x = points[i + 1].y.square() - points[out_idx].x;
- // y_3 = lambda * (x_1 - x_3) - y_1
- points[out_idx].y =
- points[i + 1].y * (points[i].x - points[out_idx].x) - points[i].y;
- }
- }
- };
-}
-
 #[macro_export]
 macro_rules! endo {
  ($name:ident, $field:ident, $params:expr) => {

src/grumpkin/curve.rs

@@ -6,11 +6,11 @@ use crate::grumpkin::Fq;
 use crate::grumpkin::Fr;
 use crate::hash_to_curve::svdw_hash_to_curve;
 use crate::{
- batch_add, impl_add_binop_specify_output, impl_binops_additive,
- impl_binops_additive_specify_output, impl_binops_multiplicative,
- impl_binops_multiplicative_mixed, impl_sub_binop_specify_output, new_curve_impl,
+ impl_add_binop_specify_output, impl_binops_additive, impl_binops_additive_specify_output,
+ impl_binops_multiplicative, impl_binops_multiplicative_mixed, impl_sub_binop_specify_output,
+ new_curve_impl,
 };
-use crate::{Coordinates, CurveAffine, CurveAffineExt, CurveExt};
+use crate::{Coordinates, CurveAffine, CurveExt};
 use core::cmp;
 use core::fmt::Debug;
 use core::iter::Sum;
@@ -35,14 +35,6 @@ new_curve_impl!(
  |curve_id, domain_prefix| svdw_hash_to_curve(curve_id, domain_prefix, G1::SVDW_Z),
 );
 
-impl CurveAffineExt for G1Affine {
- batch_add!();
-
- fn into_coordinates(self) -> (Self::Base, Self::Base) {
- (self.x, self.y)
- }
-}
-
 // Parameters in montgomery form taken from
 // https://github.com/AztecProtocol/barretenberg/blob/97ccf76c42db581a8b8f8bfbcffe8ca015a3dd22/cpp/src/barretenberg/ecc/curves/grumpkin/grumpkin.hpp#L14
 const G1_GENERATOR_X: Fq = Fq::one();

src/lib.rs

@@ -10,7 +10,6 @@ pub mod secp256r1;
 
 #[macro_use]
 mod derive;
-pub use arithmetic::CurveAffineExt;
 pub use pasta_curves::arithmetic::{Coordinates, CurveAffine, CurveExt};
 
 // Re-export ff and group to simplify down stream dependencies

src/pasta/mod.rs

@@ -9,32 +9,6 @@ use ff::WithSmallOrderMulGroup;
 pub use pasta_curves::{pallas, vesta, Ep, EpAffine, Eq, EqAffine, Fp, Fq};
 use std::convert::TryInto;
 
-impl crate::CurveAffineExt for EpAffine {
- fn batch_add<const COMPLETE: bool, const LOAD_POINTS: bool>(
- _: &mut [Self],
- _: &[u32],
- _: usize,
- _: usize,
- _: &[Self],
- _: &[u32],
- ) {
- unimplemented!();
- }
-}
-
-impl crate::CurveAffineExt for EqAffine {
- fn batch_add<const COMPLETE: bool, const LOAD_POINTS: bool>(
- _: &mut [Self],
- _: &[u32],
- _: usize,
- _: usize,
- _: &[Self],
- _: &[u32],
- ) {
- unimplemented!();
- }
-}
-
 // Generated using https://github.com/ConsenSys/gnark-crypto/blob/master/ecc/utils.go
 // with `pasta_curves::Fp::ZETA`
 // See https://github.com/demining/Endomorphism-Secp256k1/blob/main/README.md

src/secp256k1/curve.rs

@@ -3,7 +3,7 @@ use crate::ff::{Field, PrimeField};
 use crate::group::{prime::PrimeCurveAffine, Curve, Group as _, GroupEncoding};
 use crate::secp256k1::Fp;
 use crate::secp256k1::Fq;
-use crate::{Coordinates, CurveAffine, CurveAffineExt, CurveExt};
+use crate::{Coordinates, CurveAffine, CurveExt};
 use core::cmp;
 use core::fmt::Debug;
 use core::iter::Sum;
@@ -48,9 +48,9 @@ const SECP_A: Fp = Fp::from_raw([0, 0, 0, 0]);
 const SECP_B: Fp = Fp::from_raw([7, 0, 0, 0]);
 
 use crate::{
- batch_add, impl_add_binop_specify_output, impl_binops_additive,
- impl_binops_additive_specify_output, impl_binops_multiplicative,
- impl_binops_multiplicative_mixed, impl_sub_binop_specify_output, new_curve_impl,
+ impl_add_binop_specify_output, impl_binops_additive, impl_binops_additive_specify_output,
+ impl_binops_multiplicative, impl_binops_multiplicative_mixed, impl_sub_binop_specify_output,
+ new_curve_impl,
 };
 
 new_curve_impl!(
@@ -67,14 +67,6 @@ new_curve_impl!(
  |_, _| unimplemented!(),
 );
 
-impl CurveAffineExt for Secp256k1Affine {
- batch_add!();
-
- fn into_coordinates(self) -> (Self::Base, Self::Base) {
- (self.x, self.y)
- }
-}
-
 #[test]
 fn test_curve() {
  crate::tests::curve::curve_tests::<Secp256k1>();

src/secp256r1/curve.rs

@@ -3,7 +3,7 @@ use crate::ff::{Field, PrimeField};
 use crate::group::{prime::PrimeCurveAffine, Curve, Group as _, GroupEncoding};
 use crate::secp256r1::Fp;
 use crate::secp256r1::Fq;
-use crate::{Coordinates, CurveAffine, CurveAffineExt, CurveExt};
+use crate::{Coordinates, CurveAffine, CurveExt};
 use core::cmp;
 use core::fmt::Debug;
 use core::iter::Sum;
@@ -59,9 +59,9 @@ const SECP_B: Fp = Fp::from_raw([
 ]);
 
 use crate::{
- batch_add, impl_add_binop_specify_output, impl_binops_additive,
- impl_binops_additive_specify_output, impl_binops_multiplicative,
- impl_binops_multiplicative_mixed, impl_sub_binop_specify_output, new_curve_impl,
+ impl_add_binop_specify_output, impl_binops_additive, impl_binops_additive_specify_output,
+ impl_binops_multiplicative, impl_binops_multiplicative_mixed, impl_sub_binop_specify_output,
+ new_curve_impl,
 };
 
 new_curve_impl!(
@@ -78,14 +78,6 @@ new_curve_impl!(
  |_, _| unimplemented!(),
 );
 
-impl CurveAffineExt for Secp256r1Affine {
- batch_add!();
-
- fn into_coordinates(self) -> (Self::Base, Self::Base) {
- (self.x, self.y)
- }
-}
-
 #[test]
 fn test_curve() {
  crate::tests::curve::curve_tests::<Secp256r1>();