gen_key_demo.cc

int generate_keys(std::string pubkeyfile, std::string privkeyfile, std::string curve_name)
{
    EC_KEY *keygen;
    int nid = to_nid(curve_name);

    if (nid == -1) {
        return -1;
    }

    // get curve name
    keygen = EC_KEY_new_by_curve_name(nid);
    if (!keygen) {
        ERR_print_errors_fp(stderr);
        return -1;
    }

    int ret;

    // run the key generation .. we aren't doing the curve parameters
    ret = EC_KEY_generate_key(keygen);
    if (ret != 1) {
        ERR_print_errors_fp(stderr);
        return -1;
    }

    ret = EC_KEY_check_key(keygen);
    if (ret != 1) {
        ERR_print_errors_fp(stderr);
        return -1;
    }


    // wirte the keys
    FILE *fp;

    fp = fopen(pubkeyfile.c_str(), "w");
    if (!fp) {
        return -1;
    }

    PEM_write_EC_PUBKEY(fp, keygen);

    fclose(fp);

    fp = fopen(privkeyfile.c_str(), "w");
    if (!fp) {
        return -1;
    }

    PEM_write_ECPrivateKey(fp, keygen, NULL, NULL, 0, NULL, NULL);

    fclose(fp);

    EC_KEY_free(keygen);

    std::cout << "keygen success" << std::endl;
    return 0;
}