view libtommath/bn_mp_prime_rabin_miller_trials.c @ 1734:73646de50f13DROPBEAR_2020.80

version 2020.80
author Matt Johnston Fri, 26 Jun 2020 21:45:59 +0800 1051e4eea25a
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```#include "tommath_private.h"
#ifdef BN_MP_PRIME_RABIN_MILLER_TRIALS_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */

static const struct {
int k, t;
} sizes[] = {
{    80, -1 }, /* Use deterministic algorithm for size <= 80 bits */
{    81, 37 }, /* max. error = 2^(-96)*/
{    96, 32 }, /* max. error = 2^(-96)*/
{   128, 40 }, /* max. error = 2^(-112)*/
{   160, 35 }, /* max. error = 2^(-112)*/
{   256, 27 }, /* max. error = 2^(-128)*/
{   384, 16 }, /* max. error = 2^(-128)*/
{   512, 18 }, /* max. error = 2^(-160)*/
{   768, 11 }, /* max. error = 2^(-160)*/
{   896, 10 }, /* max. error = 2^(-160)*/
{  1024, 12 }, /* max. error = 2^(-192)*/
{  1536, 8  }, /* max. error = 2^(-192)*/
{  2048, 6  }, /* max. error = 2^(-192)*/
{  3072, 4  }, /* max. error = 2^(-192)*/
{  4096, 5  }, /* max. error = 2^(-256)*/
{  5120, 4  }, /* max. error = 2^(-256)*/
{  6144, 4  }, /* max. error = 2^(-256)*/
{  8192, 3  }, /* max. error = 2^(-256)*/
{  9216, 3  }, /* max. error = 2^(-256)*/
{ 10240, 2  }  /* For bigger keysizes use always at least 2 Rounds */
};

/* returns # of RM trials required for a given bit size */
int mp_prime_rabin_miller_trials(int size)
{
int x;

for (x = 0; x < (int)(sizeof(sizes)/(sizeof(sizes[0]))); x++) {
if (sizes[x].k == size) {
return sizes[x].t;
} else if (sizes[x].k > size) {
return (x == 0) ? sizes[0].t : sizes[x - 1].t;
}
}
return sizes[x-1].t;
}

#endif
```