BGN2/bgn2/src/PublicKey.cpp

#include "PublicKey.hpp"

PublicKey(const Bipoint<curvepoint_fp_t>& g, const Bipoint<twistpoint_fp2_t>& h, const Bipoint<curvepoint_fp_t>& g1, const Bipoint<twistpoint_fp2_t>& h1)
{
    set(g, h, g1, h1);
}

void set(const Bipoint<curvepoint_fp_t>& g, const Bipoint<twistpoint_fp2_t>& h, const Bipoint<curvepoint_fp_t>& g1, const Bipoint<twistpoint_fp2_t>& h1)
{
    bipoint_curvegen = g;
    bipoint_twistgen = h;
    
    bipoint_curve_subgroup_gen = g1;
    bipoint_twist_subgroup_gen = h1;
}

void PublicKey::encrypt(Bipoint<curvepoint_fp_t>& G_element, const Scalar& cleartext) const
{
    Scalar lambda;
    lambda.set_random();

    Bipoint<curvepoint_fp_t> cleartext_as_element, random_mask;
    cleartext_as_element = get_bipoint_curvegen() * cleartext;
    random_mask = get_bipoint_curve_subgroup_gen() * lambda;

    G_element = cleartext_as_element + random_mask;
}

void PublicKey::encrypt(Bipoint<twistpoint_fp2_t>& H_element, const Scalar& cleartext) const
{
    Scalar lambda;
    lambda.set_random();

    Bipoint<twistpoint_fp2_t> cleartext_as_element, random_mask;
    cleartext_as_element = get_bipoint_twistgen() * cleartext;
    random_mask = get_bipoint_twist_subgroup_gen() * lambda;

    H_element = cleartext_as_element + random_mask;
}

void PublicKey::encrypt(Bipoint<curvepoint_fp_t>& G_element, Bipoint<twistpoint_fp2_t>& H_element, const Scalar& cleartext) const
{
    encrypt(G_element, cleartext);
    encrypt(H_element, cleartext);
}

Bipoint<curvepoint_fp_t> PublicKey::get_bipoint_curvegen() const
{
    return bipoint_curvegen;
}

Bipoint<twistpoint_fp2_t> PublicKey::get_bipoint_twistgen() const
{
    return bipoint_twistgen;
}

Bipoint<curvepoint_fp_t> PublicKey::get_bipoint_curve_subgroup_gen() const
{
    return bipoint_curve_subgroup_gen;
}

Bipoint<twistpoint_fp2_t> PublicKey::get_bipoint_twist_subgroup_gen() const
{
    return bipoint_twist_subgroup_gen;
}