feat: add secq256k1 (privacy-scaling-explorations#65)

* feat: add secq256k1

* fix: update generator point

* feat: add svdw_hash_to_curve for secp

* chore: rust fmt

src/lib.rs

@@ -7,6 +7,7 @@ pub mod grumpkin;
 pub mod pasta;
 pub mod secp256k1;
 pub mod secp256r1;
+pub mod secq256k1;
 
 #[macro_use]
 mod derive;

src/secp256k1/curve.rs

@@ -1,6 +1,7 @@
 use crate::ff::WithSmallOrderMulGroup;
 use crate::ff::{Field, PrimeField};
 use crate::group::{prime::PrimeCurveAffine, Curve, Group as _, GroupEncoding};
+use crate::hash_to_curve::svdw_hash_to_curve;
 use crate::secp256k1::Fp;
 use crate::secp256k1::Fq;
 use crate::{Coordinates, CurveAffine, CurveExt};
@@ -64,14 +65,23 @@ new_curve_impl!(
  SECP_A,
  SECP_B,
  "secp256k1",
- |_, _| unimplemented!(),
+ |curve_id, domain_prefix| svdw_hash_to_curve(curve_id, domain_prefix, Secp256k1::SVDW_Z),
 );
 
+impl Secp256k1 {
+ const SVDW_Z: Fp = Fp::ONE;
+}
+
 #[test]
 fn test_curve() {
  crate::tests::curve::curve_tests::<Secp256k1>();
 }
 
+#[test]
+fn test_hash_to_curve() {
+ crate::tests::curve::hash_to_curve_test::<Secp256k1>();
+}
+
 #[test]
 fn test_serialization() {
  crate::tests::curve::random_serialization_test::<Secp256k1>();

src/secq256k1/curve.rs

@@ -0,0 +1,104 @@
+use crate::ff::WithSmallOrderMulGroup;
+use crate::ff::{Field, PrimeField};
+use crate::group::Curve;
+use crate::group::{prime::PrimeCurveAffine, Group, GroupEncoding};
+use crate::hash_to_curve::svdw_hash_to_curve;
+use crate::secp256k1::{Fp, Fq};
+use crate::{
+ 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, CurveExt};
+use core::cmp;
+use core::fmt::Debug;
+use core::iter::Sum;
+use core::ops::{Add, Mul, Neg, Sub};
+use rand::RngCore;
+use subtle::{Choice, ConditionallySelectable, ConstantTimeEq, CtOption};
+
+#[cfg(feature = "derive_serde")]
+use serde::{Deserialize, Serialize};
+
+const SECQ_GENERATOR_X: Fq = Fq::from_raw([
+ 0xA24288E37702EDA6,
+ 0x3134E45A097781A6,
+ 0xB6B06C87A2CE32E2,
+ 0x76C39F5585CB160E,
+]);
+
+const SECQ_GENERATOR_Y: Fq = Fq::from_raw([
+ 0xA4120DDAD952677F,
+ 0xD18983D26E8DC055,
+ 0xDC2D265A8E82A7F7,
+ 0x3FFC646C7B2918B5,
+]);
+
+const SECQ_A: Fq = Fq::from_raw([0, 0, 0, 0]);
+const SECQ_B: Fq = Fq::from_raw([7, 0, 0, 0]);
+
+new_curve_impl!(
+ (pub),
+ Secq256k1,
+ Secq256k1Affine,
+ true,
+ Fq,
+ Fp,
+ (SECQ_GENERATOR_X, SECQ_GENERATOR_Y),
+ SECQ_A,
+ SECQ_B,
+ "secq256k1",
+ |curve_id, domain_prefix| svdw_hash_to_curve(curve_id, domain_prefix, Secq256k1::SVDW_Z),
+);
+
+impl group::cofactor::CofactorGroup for Secq256k1 {
+ type Subgroup = Secq256k1;
+
+ fn clear_cofactor(&self) -> Self {
+ *self
+ }
+
+ fn into_subgroup(self) -> CtOption<Self::Subgroup> {
+ CtOption::new(self, 1.into())
+ }
+
+ fn is_torsion_free(&self) -> Choice {
+ 1.into()
+ }
+}
+
+impl Secq256k1 {
+ const SVDW_Z: Fq = Fq::ONE;
+}
+
+#[cfg(test)]
+mod tests {
+ use crate::secq256k1::Fq;
+ use crate::CurveExt;
+ use ff::WithSmallOrderMulGroup;
+
+ use super::Secq256k1;
+
+ #[test]
+ fn test_hash_to_curve() {
+ crate::tests::curve::hash_to_curve_test::<Secq256k1>();
+ }
+
+ #[test]
+ fn test_curve() {
+ crate::tests::curve::curve_tests::<Secq256k1>();
+ }
+
+ #[test]
+ fn test_endo_consistency() {
+ let g = Secq256k1::generator();
+ assert_eq!(g * Fq::ZETA, g.endo());
+ }
+
+ #[test]
+ fn test_serialization() {
+ crate::tests::curve::random_serialization_test::<Secq256k1>();
+ #[cfg(feature = "derive_serde")]
+ crate::tests::curve::random_serde_test::<Secq256k1>();
+ }
+}

src/secq256k1/mod.rs

@@ -0,0 +1,4 @@
+mod curve;
+
+pub use crate::secp256k1::{Fp as Fq, Fq as Fp};
+pub use curve::*;