BUGS:
  timeout on client connect too long (system default)
  Is 3 seconds timeout OK? (both client and server)

nts_log_ssl_error()  No SSL param ??
  ERR_error_string_n

Hourly logging?
  ntpq get totals vs recent

documentation:
  HOWTO on certificates
  glossary: https://letsencrypt.org/docs/glossary/

Startup with bad time

? thread per instance on NTS-KE server

Password for certificate's private key and cookie keys file.
  Need to get it before daemon mode.

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security level

client certificates

Pool/cluster mode
  ??  Ratchet for new cookie key

