public Map<String, String> subjectAltNames() {
        Map<String, String> san = new HashMap<>();
        int i = 0;
        for (String name : dnsNames()) {
            san.put("DNS." + (i++), name);
        }
        i = 0;
        for (String ip : ipAddresses()) {
            san.put("IP." + (i++), ip);
        }
        return san;
    }
@Test
    public void testIPV6()   {
        Subject subject = new Subject.Builder()
                .withCommonName("joe")
                .addIpAddress("fc01::8d1c")
                .addIpAddress("1762:0000:0000:00:0000:0B03:0001:AF18")
                .addIpAddress("1974:0:0:0:0:B03:1:AF74")
                .build();
        assertEquals(Map.of(
                        "IP.0", "fc01:0:0:0:0:0:0:8d1c",
                        "IP.1", "1974:0:0:0:0:b03:1:af74",
                        "IP.2", "1762:0:0:0:0:b03:1:af18"),
                subject.subjectAltNames());
    }