module type TLS_UTILS =
sig
  type authenticator = X509_lwt.authenticator Lwt.t
  type ciphers = Tls.Ciphersuite.ciphersuite list

  val null_auth : authenticator

  val ca : Lwt_io.file_name -> authenticator

  val self_sign : ?bits:int -> ?days:int
    -> X509.Distinguished_name.t
    -> (Tls.Config.certchain, string) result
end

module TlsUtils : TLS_UTILS