kc3-lang/libtommath/etc/2kprime.c

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• Hash : 3ed52404
  Author :
  Date : 2018-12-25T15:15:30
  

  `make astyle` + some manual adjustments

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• etc/2kprime.c

• /* Makes safe primes of a 2k nature */
  #include <tommath.h>
  #include <time.h>
  
  static int sizes[] = {256, 512, 768, 1024, 1536, 2048, 3072, 4096};
  
  int main(void)
  {
     char buf[2000];
     size_t x;
     int y;
     mp_int q, p;
     FILE *out;
     clock_t t1;
     mp_digit z;
  
     mp_init_multi(&q, &p, NULL);
  
     out = fopen("2kprime.1", "w");
     if (out != NULL) {
        for (x = 0; x < (sizeof(sizes) / sizeof(sizes[0])); x++) {
  top:
           mp_2expt(&q, sizes[x]);
           mp_add_d(&q, 3uL, &q);
           z = -3;
  
           t1 = clock();
           for (;;) {
              mp_sub_d(&q, 4uL, &q);
              z += 4uL;
  
              if (z > MP_MASK) {
                 printf("No primes of size %d found\n", sizes[x]);
                 break;
              }
  
              if ((clock() - t1) > CLOCKS_PER_SEC) {
                 printf(".");
                 fflush(stdout);
                 /*            sleep((clock() - t1 + CLOCKS_PER_SEC/2)/CLOCKS_PER_SEC); */
                 t1 = clock();
              }
  
              /* quick test on q */
              mp_prime_is_prime(&q, 1, &y);
              if (y == 0) {
                 continue;
              }
  
              /* find (q-1)/2 */
              mp_sub_d(&q, 1uL, &p);
              mp_div_2(&p, &p);
              mp_prime_is_prime(&p, 3, &y);
              if (y == 0) {
                 continue;
              }
  
              /* test on q */
              mp_prime_is_prime(&q, 3, &y);
              if (y == 0) {
                 continue;
              }
  
              break;
           }
  
           if (y == 0) {
              ++sizes[x];
              goto top;
           }
  
           mp_toradix(&q, buf, 10);
           printf("\n\n%d-bits (k = %lu) = %s\n", sizes[x], z, buf);
           fprintf(out, "%d-bits (k = %lu) = %s\n", sizes[x], z, buf);
           fflush(out);
        }
        fclose(out);
     }
  
     return 0;
  }
  
  /* ref:         $Format:%D$ */
  /* git commit:  $Format:%H$ */
  /* commit time: $Format:%ai$ */
  

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