static void
dm_ddh_setup_dec(struct dm_ddh_crs *crs, struct params *p)
{
mpz_t x, y;
int file;
unsigned long seed;
mpz_inits(x, y, NULL);
/* fix seed of random number generator */
gmp_randseed_ui(p->rnd, 0UL);
find_generator(crs->g0, p);
random_element(y, p);
mpz_powm(crs->g1, crs->g0, y, p->p);
mpz_powm(crs->h0, crs->g0, x, p->p);
mpz_powm(crs->h1, crs->g1, x, p->p);
mpz_clears(x, y, NULL);
/* re-seed random number generator */
if ((file = open("/dev/urandom", O_RDONLY)) == -1) {
(void) fprintf(stderr, "Error opening /dev/urandom\n");
} else {
if (read(file, &seed, sizeof seed) == -1) {
(void) fprintf(stderr, "Error reading from /dev/urandom\n");
(void) close(file);
}
}
gmp_randseed_ui(p->rnd, seed);
(void) close(file);
}
static fftw_rader_data *create_rader_aux(int p, int flags)
{
fftw_complex *omega, *work;
int g, ginv, gpower;
int i;
FFTW_TRIG_REAL twoPiOverN;
fftw_real scale = 1.0 / (p - 1); /* for convolution */
fftw_plan plan;
fftw_rader_data *d;
if (p < 2)
fftw_die("non-prime order in Rader\n");
flags &= ~FFTW_IN_PLACE;
d = (fftw_rader_data *) fftw_malloc(sizeof(fftw_rader_data));
g = find_generator(p);
ginv = power_mod(g, p - 2, p);
omega = (fftw_complex *) fftw_malloc((p - 1) * sizeof(fftw_complex));
plan = fftw_create_plan(p - 1, FFTW_FORWARD,
flags & ~FFTW_NO_VECTOR_RECURSE);
work = (fftw_complex *) fftw_malloc((p - 1) * sizeof(fftw_complex));
twoPiOverN = FFTW_K2PI / (FFTW_TRIG_REAL) p;
gpower = 1;
for (i = 0; i < p - 1; ++i) {
c_re(work[i]) = scale * FFTW_TRIG_COS(twoPiOverN * gpower);
c_im(work[i]) = FFTW_FORWARD * scale * FFTW_TRIG_SIN(twoPiOverN
* gpower);
gpower = MULMOD(gpower, ginv, p);
}
/* fft permuted roots of unity */
fftw_executor_simple(p - 1, work, omega, plan->root, 1, 1,
plan->recurse_kind);
fftw_free(work);
d->plan = plan;
d->omega = omega;
d->g = g;
d->ginv = ginv;
d->p = p;
d->flags = flags;
d->refcount = 1;
d->next = NULL;
d->cdesc = (fftw_codelet_desc *) fftw_malloc(sizeof(fftw_codelet_desc));
d->cdesc->name = NULL;
d->cdesc->codelet = NULL;
d->cdesc->size = p;
d->cdesc->dir = FFTW_FORWARD;
d->cdesc->type = FFTW_RADER;
d->cdesc->signature = g;
d->cdesc->ntwiddle = 0;
d->cdesc->twiddle_order = NULL;
return d;
}