Finished key generator

keygen.c

@@ -0,0 +1,143 @@
+
+#include "randsource.h"
+#include "sgprime.h"
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+
+#define RAND_SIZE 512
+#define CHUNK_SIZE 1
+
+int main(int argc, char **argv)
+{
+  unsigned int threads;
+  unsigned int bits;
+  FILE *keyoutf;
+
+  if (argc < 3 || argc > 4)
+  {
+    printf("Usage: %s <bits> <output file> [threads]\n", argv[0]);
+    return 0;
+  }
+
+  if (argc == 3)
+  {
+    threads = 0;
+  } else
+  {
+    if (1 != sscanf(argv[3], "%u", &threads) || threads == 0)
+    {
+      printf("number of threads must be a positive integer\n");
+      return 0;
+    }
+
+  }
+
+  if (1 != sscanf(argv[1], "%u", &bits) || bits == 0)
+  {
+    printf("number of bits must be a positive integer\n");
+    return 0;
+  }
+
+  keyoutf = fopen(argv[2], "w");
+  if (keyoutf == NULL)
+  {
+    perror("could not open key out file: ");
+    return 1;
+  }
+
+  printf("Key Generation Tool\n");
+
+  printf("generating a key with %u bits ...\n", bits);
+
+  fflush(stdout);
+
+  mpz_t l, p, seed, rc, g, t;
+  mpz_init(p);
+  mpz_init(l);
+  mpz_init(g);
+  mpz_init(t);
+  mpz_init(seed);
+
+  mpz_set_ui(l, 0);
+  mpz_setbit(l, bits);
+
+  unsigned long int offset, primorial;
+  void *difflist = make_difflist(l, &offset, &primorial);
+
+  gmp_randstate_t rs;
+  gmp_randinit_default(rs);
+
+  char *randbuff = malloc(RAND_SIZE);
+  if (fill_random(randbuff, RAND_SIZE))
+  {
+    perror("unable to read randomness source: ");
+    return 2;
+  }
+
+  mpz_import(seed, RAND_SIZE, 1, 1, 0, 0, randbuff);
+  gmp_randseed(rs, seed);
+
+  free(randbuff);
+
+  mpz_urandomb(p, rs, bits);
+  mpz_setbit(p, bits);
+
+  printf("generating safe prime ... ");
+  fflush(stdout);
+  get_sg_prime(difflist, offset, primorial, p, threads, bits + 4, CHUNK_SIZE);
+  printf("done\n");
+  fflush(stdout);
+
+  destroy_difflist(difflist);
+
+  mpz_mul_ui(l, p, 2);
+
+  rc[0] = seed[0]; // Moving variable names -- not portable
+  mpz_set(rc, l);
+
+  mpz_add_ui(l, l, 1);
+
+  printf("finding a generator ... ");
+  fflush(stdout);
+  while (1)
+  {
+    mpz_urandomm(g, rs, rc);
+    mpz_add_ui(rc, rc, 1);
+    mpz_powm_ui(t, g, 2, l);
+    if (mpz_cmp_ui(g, 1) != 0)
+    {
+      mpz_powm(t, g, p, l);
+      if (mpz_cmp_ui(g, 1) != 0)
+        break;
+    }
+  }
+  printf("done\n");
+  fflush(stdout);
+
+  printf("creating a secret exponent ... ");
+  fflush(stdout);
+  mpz_urandomm(p, rs, l);
+  printf("done\n");
+  fflush(stdout);
+
+  printf("computing public point ... ");
+  fflush(stdout);
+  mpz_powm(rc, g, p, l);
+  printf("done\n");
+  fflush(stdout);
+
+  gmp_randclear(rs);
+
+  gmp_fprintf(keyoutf, "m=%Zd\ng=%Zd\nx=%Zd\np=%Zd\n", l, g, p, rc);
+
+  mpz_clear(seed);
+  mpz_clear(p);
+  mpz_clear(l);
+  mpz_clear(g);
+  mpz_clear(t);
+
+  fclose(keyoutf);
+}
+

randsource.c

@@ -0,0 +1,20 @@
+// Change this file if your system uses a different randomness source.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+
+int fill_random(void *buf, int size)
+{
+  FILE *random = fopen("/dev/urandom", "r");
+  
+  if (!random)
+  {
+    return errno;
+  }
+
+  fread(buf, size, 1, random);
+  fclose(random);
+  return 0;
+}
+

randsource.h

@@ -0,0 +1,8 @@
+
+#ifndef RANDSOURCE_H
+#define RANDSOURCE_H
+
+int fill_random(void *buf, int size);
+
+#endif
+

sgprime.h

@@ -3,8 +3,8 @@
 
 #include <gmp.h>
 
-void *make_difflist(mpz_t lower_bound, unsigned long int *offset);
-mpz_t get_sg_prime(void *difflist, unsigned long int offset, unsigned long int primorial, mpz_t start_search, unsigned int threads, unsigned int reps, unsigned int chunksize)
+void *make_difflist(mpz_t lower_bound, unsigned long int *offset, unsigned long int *primorial);
+void get_sg_prime(void *difflist, unsigned long int offset, unsigned long int primorial, mpz_t start_search, unsigned int threads, unsigned int reps, unsigned int chunksize);
 void destroy_difflist(void *difflist);