1use ark_ec::{
 2    models::CurveConfig,
 3    scalar_mul::glv::GLVConfig,
 4    short_weierstrass::{self as sw, SWCurveConfig},
 5};
 6use ark_ff::{AdditiveGroup, BigInt, Field, MontFp, PrimeField, Zero};
 7
 8use crate::{fq::Fq, fr::Fr};
 9
10#[cfg(test)]
11mod tests;
12
13#[derive(Copy, Clone, Default, PartialEq, Eq)]
14pub struct PallasConfig;
15
16impl CurveConfig for PallasConfig {
17    type BaseField = Fq;
18    type ScalarField = Fr;
19
20    /// COFACTOR = 1
21    const COFACTOR: &'static [u64] = &[0x1];
22
23    /// COFACTOR_INV = 1
24    const COFACTOR_INV: Fr = Fr::ONE;
25}
26
27pub type Affine = sw::Affine<PallasConfig>;
28pub type Projective = sw::Projective<PallasConfig>;
29
30impl SWCurveConfig for PallasConfig {
31    /// COEFF_A = 0
32    const COEFF_A: Fq = Fq::ZERO;
33
34    /// COEFF_B = 5
35    const COEFF_B: Fq = MontFp!("5");
36
37    /// AFFINE_GENERATOR_COEFFS = (G1_GENERATOR_X, G1_GENERATOR_Y)
38    const GENERATOR: Affine = Affine::new_unchecked(G_GENERATOR_X, G_GENERATOR_Y);
39
40    #[inline(always)]
41    fn mul_by_a(_: Self::BaseField) -> Self::BaseField {
42        Self::BaseField::zero()
43    }
44}
45
46impl GLVConfig for PallasConfig {
47    const ENDO_COEFFS: &'static [Self::BaseField] = &[MontFp!(
48        "20444556541222657078399132219657928148671392403212669005631716460534733845831"
49    )];
50
51    const LAMBDA: Self::ScalarField =
52        MontFp!("26005156700822196841419187675678338661165322343552424574062261873906994770353");
53
54    const SCALAR_DECOMP_COEFFS: [(bool, <Self::ScalarField as PrimeField>::BigInt); 4] = [
55        (false, BigInt!("98231058071100081932162823354453065728")),
56        (true, BigInt!("98231058071186745657228807397848383489")),
57        (false, BigInt!("196462116142286827589391630752301449217")),
58        (false, BigInt!("98231058071100081932162823354453065728")),
59    ];
60
61    fn endomorphism(p: &Projective) -> Projective {
62        // Endomorphism of the points on the curve.
63        // endomorphism_p(x,y) = (BETA * x, y)
64        // where BETA is a non-trivial cubic root of unity in Fq.
65        let mut res = (*p).clone();
66        res.x *= Self::ENDO_COEFFS[0];
67        res
68    }
69
70    fn endomorphism_affine(p: &Affine) -> Affine {
71        // Endomorphism of the points on the curve.
72        // endomorphism_p(x,y) = (BETA * x, y)
73        // where BETA is a non-trivial cubic root of unity in Fq.
74        let mut res = (*p).clone();
75        res.x *= Self::ENDO_COEFFS[0];
76        res
77    }
78}
79
80/// G_GENERATOR_X = -1
81pub const G_GENERATOR_X: Fq = MontFp!("-1");
82
83/// G_GENERATOR_Y = 2
84pub const G_GENERATOR_Y: Fq = MontFp!("2");