C++ (Cpp) dv_swap_cond Examples

Example #1

File: relic_bn_mxp.c Project: Gesine/relic

void bn_mxp_monty(bn_t c, const bn_t a, const bn_t b, const bn_t m) {
	bn_t tab[2], u;
	dig_t mask;
	int t;

	bn_null(tab[0]);
	bn_null(tab[1]);
	bn_null(u);

	TRY {
		bn_new(u);
		bn_mod_pre(u, m);

		bn_new(tab[0]);
		bn_new(tab[1]);

#if BN_MOD == MONTY
		bn_set_dig(tab[0], 1);
		bn_mod_monty_conv(tab[0], tab[0], m);
		bn_mod_monty_conv(tab[1], a, m);
#else
		bn_set_dig(tab[0], 1);
		bn_copy(tab[1], a);
#endif

		for (int i = bn_bits(b) - 1; i >= 0; i--) {
			int j = bn_get_bit(b, i);
			dv_swap_cond(tab[0]->dp, tab[1]->dp, BN_DIGS, j ^ 1);
			mask = -(j ^ 1);
			t = (tab[0]->used ^ tab[1]->used) & mask;
			tab[0]->used ^= t;
			tab[1]->used ^= t;
			bn_mul(tab[0], tab[0], tab[1]);
			bn_mod(tab[0], tab[0], m, u);
			bn_sqr(tab[1], tab[1]);
			bn_mod(tab[1], tab[1], m, u);
			dv_swap_cond(tab[0]->dp, tab[1]->dp, BN_DIGS, j ^ 1);
			mask = -(j ^ 1);
			t = (tab[0]->used ^ tab[1]->used) & mask;
			tab[0]->used ^= t;
			tab[1]->used ^= t;			
		}

#if BN_MOD == MONTY
		bn_mod_monty_back(c, tab[0], m);
#else
		bn_copy(c, tab[0]);
#endif

	} CATCH_ANY {
		THROW(ERR_CAUGHT);
	}
	FINALLY {
		bn_free(tab[1]);
		bn_free(tab[0]);
		bn_free(u);
	}
}

Example #2

File: relic_ed_mul.c Project: relic-toolkit/relic

void ed_mul_monty(ed_t r, const ed_t p, const bn_t k) {
	ed_t t[2];

	ed_null(t[0]);
	ed_null(t[1]);

	if (bn_is_zero(k) || ed_is_infty(p)) {
		ed_set_infty(r);
		return;
	}

	TRY {
		ed_new(t[0]);
		ed_new(t[1]);

		ed_set_infty(t[0]);
		ed_copy(t[1], p);

		for (int i = bn_bits(k) - 1; i >= 0; i--) {
			int j = bn_get_bit(k, i);

			dv_swap_cond(t[0]->x, t[1]->x, RLC_FP_DIGS, j ^ 1);
			dv_swap_cond(t[0]->y, t[1]->y, RLC_FP_DIGS, j ^ 1);
			dv_swap_cond(t[0]->z, t[1]->z, RLC_FP_DIGS, j ^ 1);
#if ED_ADD == EXTND
			dv_swap_cond(t[0]->t, t[1]->t, RLC_FP_DIGS, j ^ 1);
#endif
			ed_add(t[0], t[0], t[1]);
			ed_dbl(t[1], t[1]);
			dv_swap_cond(t[0]->x, t[1]->x, RLC_FP_DIGS, j ^ 1);
			dv_swap_cond(t[0]->y, t[1]->y, RLC_FP_DIGS, j ^ 1);
			dv_swap_cond(t[0]->z, t[1]->z, RLC_FP_DIGS, j ^ 1);
#if ED_ADD == EXTND
			dv_swap_cond(t[0]->t, t[1]->t, RLC_FP_DIGS, j ^ 1);
#endif
		}

		ed_norm(r, t[0]);
		if (bn_sign(k) == RLC_NEG) {
			ed_neg(r, r);
		}
	} CATCH_ANY {
		THROW(ERR_CAUGHT);
	}
	FINALLY {
		ed_free(t[1]);
		ed_free(t[0]);
	}
}

Example #3

File: relic_fp_exp.c Project: Arash-Afshar/relic

void fp_exp_monty(fp_t c, const fp_t a, const bn_t b) {
	fp_t t[2];

	fp_null(t[0]);
	fp_null(t[1]);

	if (bn_is_zero(b)) {
		fp_set_dig(c, 1);
		return;
	}

	TRY {
		fp_new(t[0]);
		fp_new(t[1]);

		fp_set_dig(t[0], 1);
		fp_copy(t[1], a);

		for (int i = bn_bits(b) - 1; i >= 0; i--) {
			int j = bn_get_bit(b, i);
			dv_swap_cond(t[0], t[1], FP_DIGS, j ^ 1);
			fp_mul(t[0], t[0], t[1]);
			fp_sqr(t[1], t[1]);
			dv_swap_cond(t[0], t[1], FP_DIGS, j ^ 1);
		}

		if (bn_sign(b) == BN_NEG) {
			fp_inv(c, t[0]);
		} else {
			fp_copy(c, t[0]);
		}
	} CATCH_ANY {
		THROW(ERR_CAUGHT);
	}
	FINALLY {
		fp_free(t[1]);
		fp_free(t[0]);
	}
}