libdpf/examples/evaluation/eval_dpf3_cmp_ic.cpp

#include <cstdint>
#include <iostream>

#include "dpf.hpp"

/// Three-party comparison and interval-containment keys (one DCF share each).
int main()
{
    using Input = std::uint8_t;
    const Input thresh = 100;
    const std::uint64_t beta = 5;

    //! [eval-dpf3-cmp]
    auto [c1, c2, c3] = dpf::make_dpf3_cmp(thresh, beta);
    // Parties 1 and 3 hold the k0 half; party 2 holds k1. Open any complementary pair.
    const dpf::fp61 hot =
        dpf::reconstruct_cmp_halves(dpf::eval_point(c1, Input{10}),
            dpf::eval_point(c2, Input{10}));
    const dpf::fp61 cold =
        dpf::reconstruct_cmp_halves(dpf::eval_point(c3, Input{200}),
            dpf::eval_point(c2, Input{200}));
    //! [eval-dpf3-cmp]
    if (hot.raw() != beta || cold.raw() != 0)
    {
        std::cerr << "dpf3 cmp\n";
        return 1;
    }

    //! [eval-dpf3-ic]
    auto [i1, i2, i3] = dpf::make_dpf3_ic(Input{10}, Input{20}, Input{40}, beta);
    // Interval is relative to the public shift `r`; x=35 is on for (20,40)@r=10.
    const dpf::fp61 inside =
        dpf::reconstruct_cmp_halves(dpf::eval_point(i1, Input{35}),
            dpf::eval_point(i2, Input{35}));
    //! [eval-dpf3-ic]
    if (inside.raw() != beta)
    {
        std::cerr << "dpf3 ic\n";
        return 1;
    }

    std::cout << hot.raw() << "\n";
    return 0;
}