PemReader pemReader = new PemReader(new InputStreamReader(new FileInputStream("private_unencrypted.pem")));
        PemObject pemObject = pemReader.readPemObject();
        pemReader.close();

        KeyFactory keyFactory = KeyFactory.getInstance("RSA", "BC");
        byte[] privateKeyBytes = pemObject.getContent();
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(privateKeyBytes);
        PrivateKey privateKey = keyFactory.generatePrivate(x509KeySpec);