keymap-greenpass-init.java

private static void fetchCertificate(String resumeToken, List<String> possibleKids) throws CertificateException, IOException {

        System.out.println("Fetching new certificate");
        
        // rest call
        Response<String> resp = apiCertificate.getCertUpdate(resumeToken).execute();

        if (resp.isSuccessful()) {
            var headers = resp.headers();
            var responseKid = headers.get(HEADER_KID);
            var newResumeToken = headers.get(HEADER_RESUME_TOKEN);
            String keyString = resp.body();

            if (keyString != null && !keyString.isBlank()) {
                if (possibleKids.contains(responseKid)) {
                    PublicKey key = getPublicKey(keyString);
                    keyMap.put(responseKid, key);
                } else {
                    System.out.println(".....mumble.... this should never happen");
                }
                fetchCertificate(newResumeToken, possibleKids);
            }
        }
    }

related to medium article https://gae-piaz.medium.com/green-pass-qr-code-signature-verification-java-f742079cc88