protected List<X509Certificate> getTrustedX509Certificates()
            throws CertificateException, IOException, KeyStoreException, NoSuchAlgorithmException {
        ArrayList<X509Certificate> trustedCerts = new ArrayList<>();

        // Add the certificates from the JKS truststore - ie. the CA's of the client cert that peer Zuul's will use.
        if (serverSslConfig.getClientAuth() == ClientAuth.REQUIRE
                || serverSslConfig.getClientAuth() == ClientAuth.OPTIONAL) {
            // Get the encrypted bytes of the truststore password.
            byte[] trustStorePwdBytes;
            if (serverSslConfig.getClientAuthTrustStorePassword() != null) {
                trustStorePwdBytes = Base64.getDecoder().decode(serverSslConfig.getClientAuthTrustStorePassword());
            } else if (serverSslConfig.getClientAuthTrustStorePasswordFile() != null) {
                trustStorePwdBytes = Files.readAllBytes(
                        serverSslConfig.getClientAuthTrustStorePasswordFile().toPath());
            } else {
                throw new IllegalArgumentException(
                        "Must specify either ClientAuthTrustStorePassword or ClientAuthTrustStorePasswordFile!");
            }

            // Decrypt the truststore password.
            String trustStorePassword = getTruststorePassword(trustStorePwdBytes);

            boolean dumpDecryptedTrustStorePassword = false;
            if (dumpDecryptedTrustStorePassword) {
                LOG.debug("X509Cert Trust Store Password {}", trustStorePassword);
            }

            KeyStore trustStore = KeyStore.getInstance("JKS");
            trustStore.load(
                    new FileInputStream(serverSslConfig.getClientAuthTrustStoreFile()),
                    trustStorePassword.toCharArray());

            Enumeration<String> aliases = trustStore.aliases();
            while (aliases.hasMoreElements()) {
                X509Certificate cert = (X509Certificate) trustStore.getCertificate(aliases.nextElement());
                trustedCerts.add(cert);
            }
        }

        return trustedCerts;
    }
This function is meant to call the correct overload of {@code SslContextBuilder.forServer()}.  It should not
apply any other customization.
zuul-core/src/main/java/com/netflix/zuul/netty/ssl/BaseSslContextFactory.java