I am referring to the following. Sometimes user Tor logs contain something like this. ``` Sep 03 10:32:59.000 [warn] Certificate already expired. Either their clock is set wrong, or your clock is wrong. Sep 03 10:32:59.000 [warn] (certificate lifetime runs from Aug 16 00:00:00 2014 GMT through Jul 29 23:59:59 2015 GMT. Your time is Sep 03 10:32:59 2015 UTC.) ``` This information is interesting in context for anonymity distributions and secure network time synchronization, usability and whatnot. Used by Tails' [tordate](https://git-tails.immerda.ch/tails/tree/config/chroot_local-includes/etc/NetworkManager/dispatcher.d/20-time.sh) or Whonix's [anondate](https://www.whonix.org/wiki/Dev/TimeSync#anondate). However, these tools rely on parsing Tor's log, which is [fragile](https://labs.riseup.net/code/issues/8977). It would be nice, if something like * `certificate/valid-after` * and `certificate/valid-until` where accessible through Tor's ControlPort.