getRandomBN error when using OpenMP, if using RDSEED

[zfscgy]

I use OpenMP for parallel encrypting multiple plaintexts. However, after running for some time, the program crashes with
"getRandomBN: generate random big number error." This error is very weird since:

• It happens with OpenMP and does not happen when OpenMP is disabled.
• The error mysteriously disappears when I add some std::cout codes in the function ippGenRandomBN for debugging. I don't know why the error could be related to std::cout.
• The error happens somewhat randomly, and before the error occurs, all computation is correct.

Finally, I was able to locate the error in the ippsTRNGenRDSEED function of the ipp-crypto lib. After I change the utils.hpp to force RNGenType kRNGenType = RNGenType::PSEUDO, the error seems to be resolved.

[justalittlenoob]

Hi @zfscgy
Thanks for the info. At present, I can't reproduce this problem. If I reproduce this problem, I will fix it.
Can you try to use RNGenType::RDRAND? See if similar problems occur.

[justalittlenoob]

Hi @zfscgy
This issue is fixed with PR #59 Please have a try with the latest development branch.

[zfscgy]

Hi @zfscgy This issue is fixed with PR #59 Please have a try with the latest development branch.

Thank you very much! I have tried RDRAND and the error also disappeared. I have read PR #59 and it seems that when RDSEED fails it turns to RDRAND.

[zfscgy]

Hi @zfscgy Thanks for the info. At present, I can't reproduce this problem. If I reproduce this problem, I will fix it. Can you try to use RNGenType::RDRAND? See if similar problems occur.

Here is a simplest example:

#include <omp.h>
#include <ipcl/ipcl.hpp>



int main()
{
	ipcl::KeyPair keyPair = ipcl::generateKeypair(2048);
	std::vector<BigNumber> bignums;
	for (size_t i = 0; i < 100; i++)
	{
		bignums.push_back(BigNumber(uint32_t(i)));
	}

	for (size_t t = 0; t < 100; t++)
	{
		std::cout << "Start to encrypt 100 BigNumbers ==== time " << t << std::endl;
#pragma omp parallel for
		for (size_t i = 0; i < 100; i++)
		{
			keyPair.pub_key.encrypt(ipcl::PlainText(bignums[i]));
		}
		std::cout << "Encrypted 100 BigNumbers" << std::endl;
	}

}

And the utils.h is changed as follows:

// static const RNGenType kRNGenType = use_rdseed   ? RNGenType::RDSEED
//                                     : use_rdrand ? RNGenType::RDRAND
//                                                  : RNGenType::PSEUDO;

// #else  // compile time detection of cpu feature
// #ifdef IPCL_RNG_INSTR_RDSEED
// static const RNGenType kRNGenType = RNGenType::RDSEED;
// #elif defined(IPCL_RNG_INSTR_RDRAND)
// static const RNGenType kRNGenType = RNGenType::RDRAND;
// #else
// static const RNGenType kRNGenType = RNGenType::PSEUDO;
// #endif
#endif  // IPCL_RUNTIME_DETECT_CPU_FEATURES
static const RNGenType kRNGenType = RNGenType::RDSEED; // Change different random algorithms

Using RDSEED, the runtime error occurs at the first loop or second loop:

Start to encrypt 100 BigNumbers ==== time 0
terminate called after throwing an instance of 'std::runtime_error'
what():
File: /home/zf/projects/third-party/pailliercryptolib/ipcl/utils/common.cpp
Line: 71
Error: getRandomBN: generate random big number error.-2
terminate called recursively