kc3-lang/libtommath/bn_mp_prime_rabin_miller_trials.c

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• Hash : 1cbfbe06
  Author :
  Date : 2019-05-18T12:22:47
  

  do 2 MR rounds for numbers >=2048bits

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• bn_mp_prime_rabin_miller_trials.c

• #include "tommath_private.h"
  #ifdef BN_MP_PRIME_RABIN_MILLER_TRIALS_C
  /* LibTomMath, multiple-precision integer library -- Tom St Denis */
  /* SPDX-License-Identifier: Unlicense */
  
  static const struct {
     int k, t;
  } sizes[] = {
     {    80,    -1 }, /* Use deterministic algorithm for size <= 80 bits */
     {    81,    39 },
     {    96,    37 },
     {   128,    32 },
     {   160,    27 },
     {   192,    21 },
     {   256,    16 },
     {   384,    10 },
     {   512,     7 },
     {   640,     6 },
     {   768,     5 },
     {   896,     4 },
     {  1024,     4 },
     {  2048,     2 }  /* For bigger keysizes use always at least 2 Rounds */
  };
  
  /* returns # of RM trials required for a given bit size and max. error of 2^(-96)*/
  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
  

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