static int no_of_small_prime_numbers = DIM (small_prime_numbers) - 1;
- static unsigned int
- get_nbits (mpz_t a)
+static unsigned int
+get_nbits (mpz_t a)
{
return mpz_sizeinbase (a, 2);
}
-/**
- * Set bit N of A. and clear all bits above
- */
-static void
-set_highbit (mpz_t a, unsigned int n)
-{
- unsigned int nbits;
-
- nbits = get_nbits (a);
- while (nbits > n)
- mpz_clrbit (a, nbits--);
- mpz_setbit (a, n);
-}
-
static void
mpz_randomize (mpz_t n, unsigned int nbits, GNUNET_HashCode * rnd)
{
GNUNET_HashCode *tmp;
+ int bits_per_hc = sizeof (GNUNET_HashCode) * 8;
int cnt;
int i;
- cnt = (nbits / sizeof (GNUNET_HashCode) / 8) + 1;
+ GNUNET_assert (nbits > 0);
+ cnt = (nbits + bits_per_hc - 1) / bits_per_hc;
tmp = GNUNET_malloc (sizeof (GNUNET_HashCode) * cnt);
tmp[0] = *rnd;
{
GNUNET_CRYPTO_hash (&tmp[i], sizeof (GNUNET_HashCode), &tmp[i + 1]);
}
- *rnd = tmp[cnt - 1];
+ GNUNET_CRYPTO_hash (&tmp[i], sizeof (GNUNET_HashCode), rnd);
mpz_import (n, cnt * sizeof (GNUNET_HashCode) / sizeof (unsigned int),
1, sizeof (unsigned int), 1, 0, tmp);
GNUNET_free (tmp);
i = get_nbits (n);
while (i > nbits)
- mpz_clrbit (n, i--);
+ mpz_clrbit (n, --i);
}
/**
/* Find q and k, so that n = 1 + 2^k * q . */
mpz_init_set (q, nminus1);
- k = mpz_scan0 (q, 0);
+ k = mpz_scan1 (q, 0);
mpz_tdiv_q_2exp (q, q, k);
for (i = 0; i < steps; i++)
}
else
{
- mpz_randomize (x, nbits, hc);
-
- /* Make sure that the number is smaller than the prime and
- keep the randomness of the high bit. */
- if (mpz_tstbit (x, nbits - 2))
- {
- set_highbit (x, nbits - 2); /* Clear all higher bits. */
- }
- else
- {
- set_highbit (x, nbits - 2);
- mpz_clrbit (x, nbits - 2);
- }
+ mpz_randomize (x, nbits - 1, hc);
GNUNET_assert (mpz_cmp (x, nminus1) < 0 && mpz_cmp_ui (x, 1) > 0);
}
mpz_powm (y, x, q, n);
generating a secret prime we are most probably doing that
for RSA, to make sure that the modulus does have the
requested key size we set the 2 high order bits. */
- set_highbit (prime, nbits - 1);
+ mpz_setbit (prime, nbits - 1);
mpz_setbit (prime, nbits - 2);
mpz_setbit (prime, 0);