@mcc @whitequark Highly recommend you take a look at (and then steal) the NTP format:
https://en.wikipedia.org/wiki/Network_Time_Protocol
They also have a 128-bit version that seems... adequate:
"enough to resolve the amount of time it takes a photon to pass an electron at the speed of light. [...] enough to provide unambiguous time representation until the universe goes dim."
GNU social JP is a social network, courtesy of GNU social JP管理人. It runs on GNU social, version 2.0.2-dev, available under the GNU Affero General Public License.
All GNU social JP content and data are available under the Creative Commons Attribution 3.0 license.