int zmq::curve_client_t::decode (msg_t *msg_)
{
    zmq_assert (state == connected);

    if (msg_->size () < 33) {
        errno = EPROTO;
        return -1;
    }

    const uint8_t *message = static_cast <uint8_t *> (msg_->data ());
    if (memcmp (message, "\x07MESSAGE", 8)) {
        errno = EPROTO;
        return -1;
    }

    uint8_t message_nonce [crypto_box_NONCEBYTES];
    memcpy (message_nonce, "CurveZMQMESSAGES", 16);
    memcpy (message_nonce + 16, message + 8, 8);
    uint64_t nonce = get_uint64(message + 8);
    if (nonce <= cn_peer_nonce) {
        errno = EPROTO;
        return -1;
    }
    cn_peer_nonce = nonce;


    const size_t clen = crypto_box_BOXZEROBYTES + (msg_->size () - 16);

    uint8_t *message_plaintext = static_cast <uint8_t *> (malloc (clen));
    alloc_assert (message_plaintext);

    uint8_t *message_box = static_cast <uint8_t *> (malloc (clen));
    alloc_assert (message_box);

    memset (message_box, 0, crypto_box_BOXZEROBYTES);
    memcpy (message_box + crypto_box_BOXZEROBYTES,
            message + 16, msg_->size () - 16);

    int rc = crypto_box_open_afternm (message_plaintext, message_box,
                                      clen, message_nonce, cn_precom);
    if (rc == 0) {
        rc = msg_->close ();
        zmq_assert (rc == 0);

        rc = msg_->init_size (clen - 1 - crypto_box_ZEROBYTES);
        zmq_assert (rc == 0);

        const uint8_t flags = message_plaintext [crypto_box_ZEROBYTES];
        if (flags & 0x01)
            msg_->set_flags (msg_t::more);

        memcpy (msg_->data (),
                message_plaintext + crypto_box_ZEROBYTES + 1,
                msg_->size ());
    }
    else
        errno = EPROTO;

    free (message_plaintext);
    free (message_box);

    return rc;
}
int zmq::curve_client_t::decode (msg_t *msg_)
{
    zmq_assert (state == connected);

    if (msg_->size () < 33) {
        errno = EPROTO;
        return -1;
    }

    const uint8_t *message = static_cast <uint8_t *> (msg_->data ());
    if (memcmp (message, "\x07MESSAGE", 8)) {
        errno = EPROTO;
        return -1;
    }

    uint8_t message_nonce [crypto_box_NONCEBYTES];
    memcpy (message_nonce, "CurveZMQMESSAGES", 16);
    memcpy (message_nonce + 16, message + 8, 8);
    uint64_t nonce = get_uint64(message + 8);
    if (nonce <= cn_peer_nonce) {
        errno = EPROTO;
        return -1;
    }
    cn_peer_nonce = nonce;


    const size_t clen = crypto_box_BOXZEROBYTES + (msg_->size () - 16);

    uint8_t *message_plaintext = static_cast <uint8_t *> (malloc (clen));
    alloc_assert (message_plaintext);

    uint8_t *message_box = static_cast <uint8_t *> (malloc (clen));
    alloc_assert (message_box);

    memset (message_box, 0, crypto_box_BOXZEROBYTES);
    memcpy (message_box + crypto_box_BOXZEROBYTES,
            message + 16, msg_->size () - 16);

    int rc = crypto_box_open_afternm (message_plaintext, message_box,
                                      clen, message_nonce, cn_precom);
    if (rc == 0) {
        rc = msg_->close ();
        zmq_assert (rc == 0);

        rc = msg_->init_size (clen - 1 - crypto_box_ZEROBYTES);
        zmq_assert (rc == 0);

        const uint8_t flags = message_plaintext [crypto_box_ZEROBYTES];
        if (flags & 0x01)
            msg_->set_flags (msg_t::more);

        memcpy (msg_->data (),
                message_plaintext + crypto_box_ZEROBYTES + 1,
                msg_->size ());
    }
    else
        errno = EPROTO;

    free (message_plaintext);
    free (message_box);

    return rc;
}