1use ark_ec::{
 2    models::{ModelParameters, MontgomeryModelParameters, TEModelParameters},
 3    twisted_edwards_extended::{GroupAffine, GroupProjective},
 4};
 5use ark_ff::MontFp;
 6
 7use crate::{fq::Fq, fr::Fr};
 8
 9#[cfg(test)]
10mod tests;
11
12pub type EdwardsAffine = GroupAffine<EdwardsParameters>;
13pub type EdwardsProjective = GroupProjective<EdwardsParameters>;
14
15#[derive(Clone, Default, PartialEq, Eq)]
16pub struct EdwardsParameters;
17
18impl ModelParameters for EdwardsParameters {
19    type BaseField = Fq;
20    type ScalarField = Fr;
21
22    /// COFACTOR = 4
23    const COFACTOR: &'static [u64] = &[4];
24
25    /// COFACTOR_INV =
26    /// 527778859339273151515551558673846658209717731602102048798421311598680340096
27    const COFACTOR_INV: Fr = MontFp!(
28        Fr,
29        "527778859339273151515551558673846658209717731602102048798421311598680340096"
30    );
31}
32
33impl TEModelParameters for EdwardsParameters {
34    /// COEFF_A = -1
35    const COEFF_A: Fq = MontFp!(Fq, "-1");
36
37    /// COEFF_D = 3021
38    const COEFF_D: Fq = MontFp!(Fq, "3021");
39
40    /// Generated randomly
41    const AFFINE_GENERATOR_COEFFS: (Self::BaseField, Self::BaseField) = (GENERATOR_X, GENERATOR_Y);
42
43    type MontgomeryModelParameters = EdwardsParameters;
44
45    /// Multiplication by `a` is just negation.
46    /// Is `a` 1 or -1?
47    #[inline(always)]
48    fn mul_by_a(elem: &Self::BaseField) -> Self::BaseField {
49        -*elem
50    }
51}
52
53impl MontgomeryModelParameters for EdwardsParameters {
54    /// COEFF_A = 0x8D26E3FADA9010A26949031ECE3971B93952AD84D4753DDEDB748DA37E8F552
55    ///         = 3990301581132929505568273333084066329187552697088022219156688740916631500114
56    const COEFF_A: Fq = MontFp!(
57        Fq,
58        "3990301581132929505568273333084066329187552697088022219156688740916631500114"
59    );
60
61    /// COEFF_B = 0x9D8F71EEC83A44C3A1FBCEC6F5418E5C6154C2682B8AC231C5A3725C8170AAD
62    ///         = 4454160168295440918680551605697480202188346638066041608778544715000777738925
63    const COEFF_B: Fq = MontFp!(
64        Fq,
65        "4454160168295440918680551605697480202188346638066041608778544715000777738925"
66    );
67
68    type TEModelParameters = EdwardsParameters;
69}
70
71/// GENERATOR_X =
72/// 4497879464030519973909970603271755437257548612157028181994697785683032656389,
73const GENERATOR_X: Fq = MontFp!(
74    Fq,
75    "4497879464030519973909970603271755437257548612157028181994697785683032656389"
76);
77
78/// GENERATOR_Y =
79/// 4357141146396347889246900916607623952598927460421559113092863576544024487809
80const GENERATOR_Y: Fq = MontFp!(
81    Fq,
82    "4357141146396347889246900916607623952598927460421559113092863576544024487809"
83);