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fixed kzg #113
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@tshchelovek
tshchelovek committed Sep 1, 2023
1 parent 5ab29e8 commit 7b3e98f
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Showing 2 changed files with 29 additions and 19 deletions.
25 changes: 13 additions & 12 deletions include/nil/crypto3/zk/commitments/polynomial/kzg.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -77,8 +77,9 @@ namespace nil {
using field_type = typename curve_type::scalar_field_type;
using scalar_value_type = typename curve_type::scalar_field_type::value_type;
using commitment_key_type = std::vector<typename curve_type::template g1_type<>::value_type>;
using verification_key_type = typename curve_type::template g2_type<>::value_type;
using verification_key_type = std::array<typename curve_type::template g2_type<>::value_type, 2>;
using commitment_type = typename curve_type::template g1_type<>::value_type;
using verification_type = typename curve_type::template g2_type<>::value_type;
using proof_type = commitment_type;

struct params_type {
Expand All @@ -91,9 +92,10 @@ namespace nil {
static params_type generate(
std::size_t d, const scalar_value_type& alpha = algebra::random_element<field_type>()) {
params_type result;
result.verification_key = alpha.data;
result.verification_key[0] = alpha * verification_type::one();
result.verification_key[1] = alpha * result.verification_key[0];
result.commitment_key.reserve(d);
auto alpha_com = commitment_type::one(); // Maybe here must not be one()?
auto alpha_com = commitment_type::one();
for (std::size_t i = 0; i < d; i++) {
result.commitment_key.push_back(alpha_com);
alpha_com *= alpha.data;
Expand Down Expand Up @@ -163,7 +165,7 @@ namespace nil {
if (r != typename KZG::scalar_value_type(0)) {
throw std::runtime_error("incorrect eval or point z");
}
q /= denominator_polynom;
q = q / denominator_polynom;

return commit<KZG>(params, q);
}
Expand All @@ -187,14 +189,13 @@ namespace nil {
static bool verify_eval(const typename KZG::params_type &params,
const typename KZG::proof_type &proof,
const typename KZG::public_key_type &public_key) {
auto g2_one = KZG::curve_type::template g2_type<>::value_type::one();

auto A_1 = algebra::precompute_g1<typename KZG::curve_type>(proof);
auto A_2 = algebra::precompute_g2<typename KZG::curve_type>(
params.verification_key - public_key.z * g2_one);
params.verification_key[1] - public_key.z * params.verification_key[0]);
auto B_1 = algebra::precompute_g1<typename KZG::curve_type>(
public_key.eval * KZG::curve_type::template g1_type<>::value_type::one() - public_key.commit);
auto B_2 = algebra::precompute_g2<typename KZG::curve_type>(g2_one);
public_key.eval * params.commitment_key[0] - public_key.commit);
auto B_2 = algebra::precompute_g2<typename KZG::curve_type>(params.verification_key[0]);

typename KZG::gt_value_type gt3 = algebra::double_miller_loop<typename KZG::curve_type>(A_1, A_2, B_1, B_2);
typename KZG::gt_value_type gt_4 = algebra::final_exponentiation<typename KZG::curve_type>(gt3);
Expand Down Expand Up @@ -420,7 +421,7 @@ namespace nil {
assert(S.size() > 0);
typename math::polynomial<typename KZG::scalar_value_type> Z = {-S[0], 1};
for (std::size_t i = 1; i < S.size(); ++i) {
Z *= typename math::polynomial<typename KZG::scalar_value_type>({-S[i], 1});
Z = Z * typename math::polynomial<typename KZG::scalar_value_type>({-S[i], 1});
}
return Z;
}
Expand Down Expand Up @@ -490,8 +491,8 @@ namespace nil {
assert(denom.evaluate(s) == 0);
}
assert(spare_poly % denom == typename math::polynomial<typename KZG::scalar_value_type>({{0}}));
spare_poly /= denom;
accum += spare_poly * factor;
spare_poly = spare_poly / denom;
accum = accum + spare_poly * factor;
factor *= gamma;
}

Expand All @@ -500,7 +501,7 @@ namespace nil {
typename math::polynomial<typename KZG::scalar_value_type> right_side({{0}});
factor = KZG::scalar_value_type::one();
for (std::size_t i = 0; i < KZG::batch_size; ++i) {
right_side += factor * (polys[i] - public_key.r[i]) * set_difference_polynomial<KZG>(public_key.T, public_key.S[i]);
right_side = right_side + factor * (polys[i] - public_key.r[i]) * set_difference_polynomial<KZG>(public_key.T, public_key.S[i]);
factor *= gamma;
}
assert(accum * create_polynomial_by_zeros<KZG>(public_key.T) == right_side);
Expand Down
23 changes: 16 additions & 7 deletions test/commitment/kzg.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -69,14 +69,18 @@ BOOST_AUTO_TEST_CASE(kzg_basic_test) {
const polynomial<scalar_value_type> f = {-1, 1, 2, 3};

auto params = kzg_type::params_type::generate(n, alpha);
BOOST_CHECK(curve_type::template g1_type<>::value_type::one() == params.commitment_key[0]);
BOOST_CHECK(alpha * curve_type::template g1_type<>::value_type::one() == params.commitment_key[1]);
BOOST_CHECK(alpha * alpha * curve_type::template g1_type<>::value_type::one() == params.commitment_key[2]);
BOOST_CHECK(alpha * alpha * alpha * curve_type::template g1_type<>::value_type::one() == params.commitment_key[3]);
BOOST_CHECK(alpha * curve_type::template g2_type<>::value_type::one() == params.verification_key);
auto ck0 = params.commitment_key[0];
for (std::size_t i = 1; i < n; ++i) {
BOOST_CHECK(params.commitment_key[i] == alpha.pow(i) * ck0);
}

auto commit = zk::algorithms::commit<kzg_type>(params, f);
BOOST_CHECK(3209 * curve_type::template g1_type<>::value_type::one() == commit);

kzg_type::commitment_type check_commit = f[0] * params.commitment_key[0];
for (std::size_t i = 1; i < f.size(); ++i) {
check_commit += f[i] * params.commitment_key[i];
}
BOOST_CHECK(commit == check_commit);

typename kzg_type::public_key_type pk = {commit, z, f.evaluate(z)};
auto proof = zk::algorithms::proof_eval<kzg_type>(params, f, pk);
Expand All @@ -100,6 +104,11 @@ BOOST_AUTO_TEST_CASE(kzg_random_test) {

auto params = kzg_type::params_type::generate(n);
auto commit = zk::algorithms::commit<kzg_type>(params, f);
kzg_type::commitment_type check_commit = f[0] * params.commitment_key[0];
for (std::size_t i = 1; i < f.size(); ++i) {
check_commit += f[i] * params.commitment_key[i];
}
BOOST_CHECK(commit == check_commit);

typename kzg_type::public_key_type pk = {commit, z, f.evaluate(z)};
auto proof = zk::algorithms::proof_eval<kzg_type>(params, f, pk);
Expand Down Expand Up @@ -134,7 +143,7 @@ BOOST_AUTO_TEST_CASE(kzg_false_test) {
// wrong params
auto ck2 = params.commitment_key;
ck2[0] = ck2[0] * 2;
kzg_type::params_type params2(ck2, params.verification_key * 2);
kzg_type::params_type params2(ck2, {params.verification_key[0] * 3, params.verification_key[1]});
BOOST_CHECK(!zk::algorithms::verify_eval<kzg_type>(params2, proof, pk));

// wrong commit
Expand Down

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