Pseudo random number generator issue

[justalittlenoob]

When a machine does NOT support rdseed and rdrand instruction, IPP-Crypto S/W pseudo random number generator ippsPRNGen_BN and ippsPRNGen will be used. There will be 2 issue.

1. ippsPRNGen will cause getDJNBN or getNormalBN fall into an infinite loop, because p always equals to q.
2. ippsPRNGen_BN will cause an error like below.(provided by @xhuan28)
   

[xhuan28]

According to Intel recommendation:

"The RDSEED instruction is intended for seeding a software PRNG of arbitrary width, whereas the RDRAND is intended for applications that merely require high-quality random numbers."

Is it more reasonable to use ippsPRNGenRDRand_BN() to generate random value if both the RDSEED and RDRAND exist.

[justalittlenoob]

According to Intel recommendation:

"The RDSEED instruction is intended for seeding a software PRNG of arbitrary width, whereas the RDRAND is intended for applications that merely require high-quality random numbers."

Is it more reasonable to use ippsPRNGenRDRand_BN() to generate random value if both the RDSEED and RDRAND exist.

I don't think so. The reasons are as follows:

• ippsPRNGenRDRand_BN generates a pseudo random positive Big Number, while TRNGenRDSEED_BN generates a true random positive Big Number.
• In the performance test, there is no obvious difference between the two functions.

[justalittlenoob]

This issue is fixed with PR #54