Twisted Edwards parameters for BLS12-377

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Pending
 
+- [\#76](https://github.com/arkworks-rs/curves/pull/76) twisted Edwards parameters for bls12-377
+
 ### Breaking changes
 
 ### Features

bls12_377/src/curves/g1.rs

@@ -1,5 +1,11 @@
-use ark_ec::models::{ModelParameters, SWModelParameters};
+use ark_ec::models::{
+    twisted_edwards_extended::{
+        GroupAffine as TEGroupAffine, GroupProjective as TEGroupProjective,
+    },
+    ModelParameters, MontgomeryModelParameters, SWModelParameters, TEModelParameters,
+};
 use ark_ff::{field_new, Zero};
+use core::ops::Neg;
 
 use crate::{
     fields::{FQ_ONE, FQ_ZERO},
@@ -40,6 +46,53 @@ impl SWModelParameters for Parameters {
     }
 }
 
+pub type G1TEAffine = TEGroupAffine<Parameters>;
+pub type G1TEProjective = TEGroupProjective<Parameters>;
+
+impl TEModelParameters for Parameters {
+    /// COEFF_A = -1
+    const COEFF_A: Fq = field_new!(Fq, "-1");
+
+    /// COEFF_D = 122268283598675559488486339158635529096981886914877139579534153582033676785385790730042363341236035746924960903179 mod q
+    const COEFF_D: Fq = field_new!(Fq, "122268283598675559488486339158635529096981886914877139579534153582033676785385790730042363341236035746924960903179");
+
+    /// COFACTOR = (x - 1)^2 / 3  = 30631250834960419227450344600217059328
+    const COFACTOR: &'static [u64] = &[0x0, 0x170b5d4430000000];
+
+    /// COFACTOR_INV = COFACTOR^{-1} mod r
+    /// = 5285428838741532253824584287042945485047145357130994810877
+    #[rustfmt::skip]
+    const COFACTOR_INV: Fr = field_new!(Fr, "5285428838741532253824584287042945485047145357130994810877");
+
+    /// AFFINE_GENERATOR_COEFFS = (GENERATOR_X, GENERATOR_Y)
+    const AFFINE_GENERATOR_COEFFS: (Self::BaseField, Self::BaseField) =
+        (TE_GENERATOR_X, TE_GENERATOR_Y);
+
+    type MontgomeryModelParameters = Parameters;
+
+    /// Multiplication by `a` is multiply by `-1`.
+    #[inline(always)]
+    fn mul_by_a(elem: &Self::BaseField) -> Self::BaseField {
+        elem.neg()
+    }
+}
+
+impl MontgomeryModelParameters for Parameters {
+    /// COEFF_A = 228097355113300204138531148905234651262148041026195375645000724271212049151994375092458297304264351187709081232384
+    const COEFF_A: Fq = field_new!(
+        Fq,
+        "228097355113300204138531148905234651262148041026195375645000724271212049151994375092458297304264351187709081232384"
+    );
+
+    /// COEFF_B = 10189023633222963290707194929886294091415157242906428298294512798502806398782149227503530278436336312243746741931
+    const COEFF_B: Fq = field_new!(
+        Fq,
+        "10189023633222963290707194929886294091415157242906428298294512798502806398782149227503530278436336312243746741931"
+    );
+
+    type TEModelParameters = Parameters;
+}
+
 /// G1_GENERATOR_X =
 /// 81937999373150964239938255573465948239988671502647976594219695644855304257327692006745978603320413799295628339695
 #[rustfmt::skip]
@@ -49,3 +102,12 @@ pub const G1_GENERATOR_X: Fq = field_new!(Fq, "819379993731509642399382555734659
 /// 241266749859715473739788878240585681733927191168601896383759122102112907357779751001206799952863815012735208165030
 #[rustfmt::skip]
 pub const G1_GENERATOR_Y: Fq = field_new!(Fq, "241266749859715473739788878240585681733927191168601896383759122102112907357779751001206799952863815012735208165030");
+
+pub const TE_GENERATOR_X: Fq = field_new!(
+    Fq,
+    "71222569531709137229370268896323705690285216175189308202338047559628438110820800641278662592954630774340654489393"
+);
+pub const TE_GENERATOR_Y: Fq = field_new!(
+    Fq,
+    "6177051365529633638563236407038680211609544222665285371549726196884440490905471891908272386851767077598415378235"
+);

bls12_377/src/curves/mod.rs

@@ -31,3 +31,5 @@ pub type G1Affine = bls12::G1Affine<Parameters>;
 pub type G1Projective = bls12::G1Projective<Parameters>;
 pub type G2Affine = bls12::G2Affine<Parameters>;
 pub type G2Projective = bls12::G2Projective<Parameters>;
+
+pub use g1::{G1TEAffine, G1TEProjective};

bls12_377/src/curves/tests.rs

@@ -1,19 +1,22 @@
 #![allow(unused_imports)]
+use crate::{
+    g1, g2, Bls12_377, Fq, Fq12, Fq2, Fr, G1Affine, G1Projective, G1TEProjective, G2Affine,
+    G2Projective,
+};
+use ark_ec::{
+    models::SWModelParameters, short_weierstrass_jacobian, AffineCurve, PairingEngine,
+    ProjectiveCurve,
+};
 use ark_ff::{
     fields::{Field, FpParameters, PrimeField, SquareRootField},
     One, Zero,
 };
 use ark_serialize::CanonicalSerialize;
-use ark_std::test_rng;
-
-use ark_ec::{models::SWModelParameters, AffineCurve, PairingEngine, ProjectiveCurve};
-use ark_std::rand::Rng;
+use ark_std::{rand::Rng, test_rng};
 use core::ops::{AddAssign, MulAssign};
 
-use crate::{g1, g2, Bls12_377, Fq, Fq12, Fq2, Fr, G1Affine, G1Projective, G2Affine, G2Projective};
-
 use ark_algebra_test_templates::{
-    curves::{curve_tests, sw_tests},
+    curves::{curve_tests, edwards_tests, sw_tests},
     groups::group_test,
 };
 
@@ -22,6 +25,7 @@ fn test_g1_projective_curve() {
     curve_tests::<G1Projective>();
 
     sw_tests::<g1::Parameters>();
+    edwards_tests::<g1::Parameters>();
 }
 
 #[test]
@@ -30,6 +34,10 @@ fn test_g1_projective_group() {
     let a: G1Projective = rng.gen();
     let b: G1Projective = rng.gen();
     group_test(a, b);
+
+    let c = rng.gen();
+    let d = rng.gen();
+    group_test::<G1TEProjective>(c, d);
 }
 
 #[test]