/* Construct a generic GFMethod for arithmetic over prime fields with
* irreducible irr. */
GFMethod *
GFMethod_consGFp_mont(const mp_int *irr)
{
mp_err res = MP_OKAY;
int i;
GFMethod *meth = NULL;
mp_mont_modulus *mmm;
meth = GFMethod_consGFp(irr);
if (meth == NULL)
return NULL;
mmm = (mp_mont_modulus *) malloc(sizeof(mp_mont_modulus));
if (mmm == NULL) {
res = MP_MEM;
goto CLEANUP;
}
meth->field_mul = &ec_GFp_mul_mont;
meth->field_sqr = &ec_GFp_sqr_mont;
meth->field_div = &ec_GFp_div_mont;
meth->field_enc = &ec_GFp_enc_mont;
meth->field_dec = &ec_GFp_dec_mont;
meth->extra1 = mmm;
meth->extra2 = NULL;
meth->extra_free = &ec_GFp_extra_free_mont;
mmm->N = meth->irr;
i = mpl_significant_bits(&meth->irr);
i += MP_DIGIT_BIT - 1;
mmm->b = i - i % MP_DIGIT_BIT;
mmm->n0prime = 0 - s_mp_invmod_radix(MP_DIGIT(&meth->irr, 0));
CLEANUP:
if (res != MP_OKAY) {
GFMethod_free(meth);
return NULL;
}
return meth;
}
/* Construct a generic ECGroup for elliptic curves over prime fields. */
ECGroup *
ECGroup_consGFp(const mp_int *irr, const mp_int *curvea,
const mp_int *curveb, const mp_int *genx,
const mp_int *geny, const mp_int *order, int cofactor)
{
mp_err res = MP_OKAY;
ECGroup *group = NULL;
group = ECGroup_new();
if (group == NULL)
return NULL;
group->meth = GFMethod_consGFp(irr);
if (group->meth == NULL) {
res = MP_MEM;
goto CLEANUP;
}
MP_CHECKOK(mp_copy(curvea, &group->curvea));
MP_CHECKOK(mp_copy(curveb, &group->curveb));
MP_CHECKOK(mp_copy(genx, &group->genx));
MP_CHECKOK(mp_copy(geny, &group->geny));
MP_CHECKOK(mp_copy(order, &group->order));
group->cofactor = cofactor;
group->point_add = &ec_GFp_pt_add_aff;
group->point_sub = &ec_GFp_pt_sub_aff;
group->point_dbl = &ec_GFp_pt_dbl_aff;
group->point_mul = &ec_GFp_pt_mul_jm_wNAF;
group->base_point_mul = NULL;
group->points_mul = &ec_GFp_pts_mul_jac;
group->validate_point = &ec_GFp_validate_point;
CLEANUP:
if (res != MP_OKAY) {
ECGroup_free(group);
return NULL;
}
return group;
}
