topic Re: ipp 6.0 : RSA Encryption problem: ippsRSAGenerate crash in Intel® Integrated Performance Primitives

ipp 6.0 : RSA Encryption problem: ippsRSAGenerate crash

ndehoumon — Thu, 18 Dec 2008 01:04:20 GMT

Hi,

ippsRSAGenerate keeps crashing. What's the problem with that code:

-static const Ipp32u dataE[] = {65537};

static const int keyLen = 2048;
primeLen_ = keyLen/2;

//pseudo-random engine
int rngSize;
ippsPRNGGetSize(&rngSize);

IppsPRNGState* pRNG = (IppsPRNGState*)ippsMalloc_8u(rngSize);

int MaxSeedBitsize=512;
ippsPRNGInit(MaxSeedBitsize, pRNG);

// Give entropy to the PRNG
BigNum b(data32Len);
b.Randomize();

status=ippsPRNGSetSeed(b.GetBN(), pRNG);

...

BigNum publicExponent(sizeof(dataE)/sizeof(dataE[0]));
publicExponent.Set(1,dataE); // calls ippsSet_BN

ippsRSAGenerate(
publicExponent.GetBN(),
keyLen_,
primeLen_,
gen_t(primeLen_),
pRSADecKey_,
ippsPRNGen,
pRNG
);

with :

int gen_t(int kp)
{
int t;

t = 27;
if(kp>150) t = 18;
if(kp>200) t = 15;
if(kp>250) t = 12;
if(kp>300) t = 9;
if(kp>350) t = 8;
if(kp>400) t = 7;
if(kp>450) t = 6;
return t;
}

Any suggestions will be very helpful Thanks.

Re: ipp 6.0 : RSA Encryption problem: ippsRSAGenerate crash

Vladimir_Dudnik — Thu, 18 Dec 2008 09:49:46 GMT

The code you provide does ot compile. I would recommend you to carefully check parameters you use for IPP function call (please also refer to IPP documentation to see if any limitations have to be considered)

Vladimir

Re: ipp 6.0 : RSA Encryption problem: ippsRSAGenerate crash

ndehoumon — Thu, 18 Dec 2008 20:22:36 GMT

Quoting - vdudnik

Hi ,

Thanks for your reply. The code does actually compile. But I did not want to paste all parts in this thread. So I try to replicate a kind of pseudo-code for it.
Anyway thanks, I fixed the problem.

Now my problem with ippsRSAGenerate is the t=nTrials Security parameter specified for the Miller-Rabin probable primality . When I use nTrials values derived from the Miller-Rabin pure theory , the program takes too much time to compute. It just to much calculations.

I'm using 2048-bit and 3072-bit keys. Do you have any suggestions ( tradoffs ) about nTrials values ?

Thanks.

Re: ipp 6.0 : RSA Encryption problem: ippsRSAGenerate crash

Vladimir_Dudnik — Fri, 19 Dec 2008 06:02:23 GMT

Hello,

our expert recommend you to try something like this:

[cpp]int gen_t(int kp)
{
int t;

t = 27;
if(kp>150) t = 18;
if(kp>200) t = 15;
if(kp>250) t = 12;
if(kp>300) t = 9;
if(kp>350) t = 8;
if(kp>400) t = 7;
if(kp>450) t = 6;
return t;
}
[/cpp]

Regards,
Vladimir