export async function generatePrivateKeyFile(privateKeyFilename: string, modulusLength: 1024 | 2048 | 3072 | 4096) {
    const keys = await generateKeyPair(modulusLength);
    const privateKeyPem = await privateKeyToPEM(keys.privateKey);
    await fs.promises.writeFile(privateKeyFilename, privateKeyPem.privPem, "utf-8");
    privateKeyPem.privPem = "";