libdpf/test/tests/arith_garble_test.cpp

#include <gtest/gtest.h>

#include <cstdint>
#include <vector>

#include "dpf/arith_garble.hpp"

namespace
{

using dpf::arith_garble::circuit;
using dpf::arith_garble::wire;

std::vector<std::uint16_t> plain_outs(const circuit & c,
    const std::uint16_t * in)
{
    auto all = dpf::arith_garble::eval_plain(c, in);
    std::vector<std::uint16_t> out;
    for (auto id : c.outputs())
        out.push_back(all[id]);
    return out;
}

void expect_match(const circuit & c, const std::vector<std::uint16_t> & in)
{
    auto got = dpf::arith_garble::eval_pair(c, in.data());
    auto want = plain_outs(c, in.data());
    ASSERT_EQ(got.opened, want);
    ASSERT_EQ(got.mask.size(), want.size());
    for (std::size_t i = 0; i < want.size(); ++i)
    {
        EXPECT_EQ(got.opened[i],
            dpf::arith_garble::open_shares(got.modulus[i], got.mask[i], got.color[i]));
    }
}

}  // namespace

TEST(ArithGarble, ProjectionRowsAreModulusMinusOne)
{
    circuit c;
    auto x = c.input(5);
    std::vector<std::uint16_t> sq{0, 1, 4, 4, 1};
    c.out(c.project(x, 5, sq));
    auto got = dpf::arith_garble::eval_pair(c, std::vector<std::uint16_t>{3}.data());
    EXPECT_EQ(got.ciphertext_rows, 4u);
    EXPECT_EQ(got.opened[0], 4u);
}

TEST(ArithGarble, AddScaleAndPublicShift)
{
    circuit c;
    auto x = c.input(7);
    auto y = c.input(7);
    auto s = c.add(x, y);
    auto t = c.scale(s, 3);
    c.out(c.add_const(t, 4));
    for (std::uint16_t a = 0; a < 7; ++a)
        for (std::uint16_t b = 0; b < 7; ++b)
            expect_match(c, {a, b});
}

TEST(ArithGarble, ThresholdCostsFanInRows)
{
    circuit c;
    std::vector<wire> bits;
    for (int i = 0; i < 3; ++i)
        bits.push_back(c.input(4));
    c.out(c.threshold(bits, 3));
    auto got = dpf::arith_garble::eval_pair(
        c, std::vector<std::uint16_t>{1, 1, 1}.data());
    EXPECT_EQ(got.ciphertext_rows, 3u);
    EXPECT_EQ(got.opened[0], 1u);
    expect_match(c, {1, 1, 0});
    expect_match(c, {0, 0, 0});
}

TEST(ArithGarble, FanInAndOfBits)
{
    circuit c;
    std::vector<wire> bits;
    for (int i = 0; i < 4; ++i)
        bits.push_back(c.input(2));
    c.out(c.fanin_and(bits));
    expect_match(c, {1, 1, 1, 1});
    expect_match(c, {1, 1, 0, 1});
    expect_match(c, {0, 0, 0, 0});
}

TEST(ArithGarble, PrimeProduct)
{
    for (std::uint16_t p : {2, 3, 5, 7})
    {
        circuit c;
        auto x = c.input(p);
        auto y = c.input(p);
        c.out(c.mul(x, y));
        for (std::uint16_t a = 0; a < p; ++a)
            for (std::uint16_t b = 0; b < p; ++b)
                expect_match(c, {a, b});
    }
}

TEST(ArithGarble, ChainedProduct)
{
    circuit c;
    auto x = c.input(5);
    auto y = c.input(5);
    auto z = c.input(5);
    c.out(c.mul(c.add(x, y), z));
    expect_match(c, {2, 4, 3});
    expect_match(c, {0, 1, 4});
    expect_match(c, {4, 4, 0});
}

TEST(ArithGarble, EveryResidueOfAProjectionAndAScale)
{
    circuit c;
    auto x = c.input(11);
    std::vector<std::uint16_t> cube(11);
    for (std::uint16_t i = 0; i < 11; ++i)
        cube[i] = static_cast<std::uint16_t>((i * i * i) % 11);
    auto y = c.project(x, 11, cube);
    c.out(y);
    c.out(c.scale(y, 10));
    c.out(c.add_const(x, 18));
    for (std::uint16_t a = 0; a < 11; ++a)
    {
        expect_match(c, {a});
        auto got = dpf::arith_garble::eval_pair(c, &a);
        EXPECT_EQ(got.ciphertext_rows, 10u);
    }
}

TEST(ArithGarble, FreeGatesSendNoRows)
{
    circuit c;
    auto x = c.input(9);
    auto y = c.input(9);
    c.out(c.add_const(c.scale(c.add(x, y), 5), 4));
    auto got = dpf::arith_garble::eval_pair(c, std::vector<std::uint16_t>{8, 8}.data());
    EXPECT_EQ(got.ciphertext_rows, 0u);
    EXPECT_EQ(got.opened[0], static_cast<std::uint16_t>((5 * (8 + 8) + 4) % 9));
}

TEST(ArithGarble, ThresholdEveryWeight)
{
    circuit c;
    std::vector<wire> bits;
    for (int i = 0; i < 5; ++i)
        bits.push_back(c.input(6));
    for (std::uint16_t t = 0; t <= 5; ++t)
        c.out(c.threshold(bits, t));
    auto one = dpf::arith_garble::eval_pair(
        c, std::vector<std::uint16_t>{1, 1, 1, 1, 1}.data());
    EXPECT_EQ(one.ciphertext_rows, 5u * 6u);
    for (unsigned mask = 0; mask < 32; ++mask)
    {
        std::vector<std::uint16_t> in(5);
        for (int i = 0; i < 5; ++i)
            in[i] = static_cast<std::uint16_t>((mask >> i) & 1u);
        expect_match(c, in);
    }
}

TEST(ArithGarble, FanInAndEveryPattern)
{
    circuit c;
    std::vector<wire> bits;
    for (int i = 0; i < 4; ++i)
        bits.push_back(c.input(2));
    c.out(c.fanin_and(bits));
    auto rows = dpf::arith_garble::eval_pair(
        c, std::vector<std::uint16_t>{1, 1, 1, 1}.data());
    EXPECT_EQ(rows.ciphertext_rows, 8u);
    for (unsigned mask = 0; mask < 16; ++mask)
    {
        std::vector<std::uint16_t> in(4);
        for (int i = 0; i < 4; ++i)
            in[i] = static_cast<std::uint16_t>((mask >> i) & 1u);
        expect_match(c, in);
    }
}

TEST(ArithGarble, PrimeElevenAndBitScale)
{
    circuit mul;
    auto x = mul.input(11);
    auto y = mul.input(11);
    mul.out(mul.mul(x, y));
    for (std::uint16_t a = 0; a < 11; ++a)
        for (std::uint16_t b = 0; b < 11; ++b)
            expect_match(mul, {a, b});

    circuit pass;
    auto word = pass.input(5);
    auto bit = pass.input(2);
    pass.out(pass.bit_scale(word, bit));
    for (std::uint16_t w = 0; w < 5; ++w)
        for (std::uint16_t b = 0; b < 2; ++b)
            expect_match(pass, {w, b});
}

TEST(ArithGarble, TwoEvalutionsOpenTheSameValue)
{
    circuit c;
    auto x = c.input(5);
    auto y = c.input(5);
    c.out(c.mul(x, y));
    const std::uint16_t in[2] = {3, 4};
    auto a = dpf::arith_garble::eval_pair(c, in);
    auto b = dpf::arith_garble::eval_pair(c, in);
    EXPECT_EQ(a.opened, b.opened);
    EXPECT_EQ(a.opened[0], static_cast<std::uint16_t>((3 * 4) % 5));
}

TEST(ArithGarble, RejectsBadModuliTablesAndInputs)
{
    circuit c;
    EXPECT_THROW(c.input(1), std::invalid_argument);
    EXPECT_THROW(c.input(129), std::invalid_argument);
    auto x = c.input(8);
    auto y = c.input(7);
    EXPECT_THROW(c.add(x, y), std::invalid_argument);
    EXPECT_THROW(c.scale(x, 2), std::invalid_argument);
    EXPECT_THROW(c.scale(x, 0), std::invalid_argument);
    EXPECT_THROW(c.project(x, 3, {0, 1}), std::invalid_argument);
    EXPECT_THROW(c.project(x, 3, std::vector<std::uint16_t>(8, 3)), std::invalid_argument);
    auto bit = c.input(2);
    EXPECT_THROW(c.bit_scale(x, x), std::invalid_argument);
    EXPECT_THROW(c.fanin_and({x}), std::invalid_argument);
    EXPECT_THROW(c.threshold({}, 0), std::invalid_argument);
    circuit bare;
    bare.input(3);
    EXPECT_THROW(dpf::arith_garble::eval_pair(bare, std::vector<std::uint16_t>{0}.data()),
        std::invalid_argument);
    circuit one;
    one.out(one.input(4));
    EXPECT_THROW(expect_match(one, {4}), std::invalid_argument);
    (void)bit;
}