C++ (Cpp) bn_mxp_dig Examples

Example #1

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

int cp_bdpe_dec(dig_t *out, uint8_t *in, int in_len, bdpe_t prv) {
	bn_t m, t, z;
	unsigned i;
	int size, result = STS_OK;

	size = bn_size_bin(prv->n);

	if (in_len < 0 || in_len != size) {
		return STS_ERR;
	}

	bn_null(m);
	bn_null(t);
	bn_null(z);

	TRY {
		bn_new(m);
		bn_new(t);
		bn_new(z);

		/* Compute t = (p-1)(q-1)/block. */
		bn_mul(t, prv->p, prv->q);
		bn_sub(t, t, prv->p);
		bn_sub(t, t, prv->q);
		bn_add_dig(t, t, 1);
		bn_div_dig(t, t, prv->t);
		bn_read_bin(m, in, in_len);
		bn_mxp(m, m, t, prv->n);
		bn_mxp(t, prv->y, t, prv->n);

		for (i = 0; i < prv->t; i++) {
			bn_mxp_dig(z, t, i, prv->n);
			if (bn_cmp(z, m) == CMP_EQ) {
				*out = i;
				break;
			}
		}

		if (i == prv->t) {
			result = STS_ERR;
		}
	} CATCH_ANY {
		result = STS_ERR;
	}
	FINALLY {
		bn_free(m);
		bn_free(t);
		bn_free(z);
	}

	return result;
}

Example #2

File: relic_cp_bdpe.c Project: Gesine/relic

int cp_bdpe_enc(uint8_t *out, int *out_len, dig_t in, bdpe_t pub) {
	bn_t m, u;
	int size, result = STS_OK;

	bn_null(m);
	bn_null(u);

	size = bn_size_bin(pub->n);

	if (in > pub->t) {
		return STS_ERR;
	}

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

		bn_set_dig(m, in);

		do {
			bn_rand(u, BN_POS, bn_bits(pub->n));
			bn_mod(u, u, pub->n);
		} while (bn_is_zero(u));

		bn_mxp(m, pub->y, m, pub->n);
		bn_mxp_dig(u, u, pub->t, pub->n);
		bn_mul(m, m, u);
		bn_mod(m, m, pub->n);

		if (size <= *out_len) {
			*out_len = size;
			memset(out, 0, *out_len);
			bn_write_bin(out, size, m);
		} else {
			result = STS_ERR;
		}
	}
	CATCH_ANY {
		result = STS_ERR;
	}
	FINALLY {
		bn_free(m);
		bn_free(u);
	}

	return result;
}