docs: public UUID fingerprint() {
          try {
              final var bb = ByteBuffer.wrap(MessageDigest.getInstance("MD5").digest(
                  serialized(Set.of(SIGNATURE_KEY, DIGEST_KEY))));
              final var ms = bb.getLong();
              final var ls = bb.getLong();
              return new UUID(ms, ls);
          } catch (final Exception e) {
              return null;
          }
      }