truetime

Cross-platform estimate of "true" time in very adverse conditions:

• offline
• unreliable/untrusted system local time (eg. user keeps changing the time forwards and/or backwards in time).
  • user may also shut down/put to sleep/hibernate system for abnormal periods of time.
• this script is NOT running in the background, and only allowed to run occasionally.

Warning: this is experimental, use at your own risk.

Usage

# install deps
pip3 install uptime ntplib
# run script
python3 ./main.py

Assumptions

• Assumes system interacts w/ temp directory files on a roughly continuous and consistent basis.

How it works

Uses an NTP server when online.

When offline, estimates time from system temp directory files.

Steps:

1. get earliest timestamp that appears trustable
   • scan all files in temp dir, storing timestamps for file creation, file modification, and file last accessed
   • calculate gaps between those timestamps
   • earliest trustable timestamp is the time before earliest gap
2. calculate how much time has elapsed since that time
   • TBD
3. add the offset to the earlier timestamp