sectok_apdu(sc_fd, CLA_SSH, INS_GET_PUBKEY, 0, 0, 0, NULL, len, n, &sw);
if (!sectok_swOK(sw)) {
error("could not obtain public key: %s", sectok_get_sw(sw));
sectok_apdu(sc_fd, CLA_SSH, INS_GET_PUBKEY, 0, 0, 0, NULL, len, n, &sw);
if (!sectok_swOK(sw)) {
error("could not obtain public key: %s", sectok_get_sw(sw));