[Bug]: OKVS测试无掩盖效果

[Yinbenxin]

Describe the bug

OKVS中实现的编码和解码逻辑应该是：Key*P=Value，P理论上应该是一个随机数组，但是我在实际测试时发现P中明显存在value数据，请问这本来就这么设计吗？还是我哪里设置有问题？

Steps To Reproduce

bazel run //psi/psi/core/vole_psi/okvs:baxos_test
//paxos_test同样存在该问题。
`
namespace psi::psi::okvs {

class BaxosTest : public testing::TestWithParamstd::size_t {};

TEST_P(BaxosTest, WORKS) {
size_t items_num = GetParam();
size_t bin_size = items_num / 4;
size_t weight = 3;
// statistical security parameter
size_t ssp = 40;

Baxos baxos;
yacl::crypto::Prg<uint128_t> prng(yacl::crypto::RandU128());

uint128_t seed;
prng.Fill(absl::MakeSpan(&seed, 1));

SPDLOG_INFO("items_num:{}, bin_size:{}", items_num, bin_size);

baxos.Init(items_num, bin_size, weight, ssp, PaxosParam::DenseType::GF128,
seed);

SPDLOG_INFO("baxos.size(): {}", baxos.size());

std::vector<uint128_t> items(items_num);
std::vector<uint128_t> values(items_num);
std::vector<uint128_t> values2(items_num);
std::vector<uint128_t> p(baxos.size());

prng.Fill(absl::MakeSpan(items.data(), items.size()));
prng.Fill(absl::MakeSpan(values.data(), values.size()));

auto start = std::chrono::high_resolution_clock::now();
baxos.Solve(absl::MakeSpan(items), absl::MakeSpan(values), absl::MakeSpan(p));
auto end = std::chrono::high_resolution_clock::now();
std::cout << "baxos.Solve size" << p.size();
std::chrono::duration<double, std::milli> elapsed = end - start;
std::cout << "baxos.Solve took " << elapsed.count() << " milliseconds.\n";

for (const auto& innerVec : p) {
// for (const auto& element : innerVec) {
std::cout << innerVec << " ";
// }
std::cout << std::endl;
}

for (const auto& innerVec : values) {
// for (const auto& element : innerVec) {
std::cout << innerVec << " ";
// }
std::cout << std::endl;
}
size_t k = 0;
for (size_t i = 0; i < values.size(); i++) {
for (size_t j = 0; j < p.size(); j++) {
if (p[j] == values[i]) {
// std::cout << "valuesp:" << i << std::endl;
k++;
}
}
}
std::cout << "count: " << k << std::endl;
start = std::chrono::high_resolution_clock::now();
baxos.Decode(absl::MakeSpan(items), absl::MakeSpan(values2),
absl::MakeSpan(p));
end = std::chrono::high_resolution_clock::now();
elapsed = end - start;
std::cout << "baxos.Decode took " << elapsed.count() << " milliseconds.\n";

if (std::memcmp(values2.data(), values.data(),
values.size() * sizeof(uint128_t)) != 0) {
for (uint64_t i = 0; i < items_num; ++i) {
EXPECT_EQ(std::memcmp(&values[i], &values2[i], sizeof(uint128_t)), 0);
}
}
}

INSTANTIATE_TEST_SUITE_P(Works_Instances, BaxosTest, testing::Values(15));

} // namespace psi::psi::okvs
`

结果：
`
Running main() from gmock_main.cc
[==========] Running 1 test from 1 test suite.
[----------] Global test environment set-up.
[----------] 1 test from Works_Instances/BaxosTest
[ RUN ] Works_Instances/BaxosTest.WORKS/0
[2024-07-05 03:27:56.630] [info] [baxos_test.cc:43] items_num:15, bin_size:3
[2024-07-05 03:27:56.631] [info] [baxos_test.cc:48] baxos.size(): 265
baxos.Solve size265baxos.Solve took 0.084167 milliseconds.
0
0
0
0
0
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0
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30249581019136461799913703116248529260
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264482226524464365223049826774360018070
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94857184957107499938021084602682390890
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282432622376067604239800030988424235940
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60542127553454401102716789245072047140
75377835026112524672441006935454381434
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36933043176152668205754522843720319017
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194629314372862775373800636331631656676
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239385172818071565953594850162918447632
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38640883360020630412977397758636309358
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38640883360020630412977397758636309358
194629314372862775373800636331631656676
57143744327010333286401672076945547235
6884410884816999675291523560055973892
297070843746093303118528725100684470190
30249581019136461799913703116248529260
94857184957107499938021084602682390890
282432622376067604239800030988424235940
60542127553454401102716789245072047140
42139514444490055029471643400844337786
75377835026112524672441006935454381434
88767996193783301854506181464606643968
264482226524464365223049826774360018070
36933043176152668205754522843720319017
239385172818071565953594850162918447632
count: 12
baxos.Decode took 0.059291 milliseconds.
[ OK ] Works_Instances/BaxosTest.WORKS/0 (1 ms)
[----------] 1 test from Works_Instances/BaxosTest (1 ms total)

[----------] Global test environment tear-down
[==========] 1 test from 1 test suite ran. (1 ms total)
[ PASSED ] 1 test.
`

Expected behavior

OKVS生成的P不显示原本value。

Version

0.4.0

Operating system

mac

Hardware Resources

16c16G

[qxzhou1010]

@Yinbenxin 感谢反馈，我们将尽快确认你提出的问题并给出回复。

[qxzhou1010]

@Yinbenxin

1. 注意到你编译目标的路径是bazel run//psi/psi/core/vole_psi/okvs.baxos_test，这是一个比较老版本的PSI的路径，建议使用最新版本的PSI。
2. 基于你提供的测试用例，在目前的PSI repo下，有编译错误，需要替换RandU128的生成接口为：yacl:crypto::Prg<uint128_t> prng(yacl::crypto::FastRandU128()));
3. 根据你提供的测试用例，我复现了跟你相同的结果，即OKVS Encode的输出P和Value中存在相等的值。但这并不是一个
   Bug，因为OKVS是用来保护key-value pair 中的 key。你可以在上述测试用例中尝试对比P和Item的值，理应没有相等的值；此外，也可以参考rr22论文查看OKVS在PSI中的使用方法。