Faketime

If trying to guard privacy, it might be desirable to adjust the create date and time when generating a new certificate or subkey. This could also be true to override the date and time of when a message is encrypted or signed (say to the nearest day) to help “leak” information. Below is a quick discussion on how several of the commands in the previous section could make use of the faketime command.

Using faketime (on *nix OS’s) will allow overriding the current time as presented to a process. We can use this to present a time of our choosing to GnuPG to override the create date time on our generated certificates. In addition, we can override the TZ environment variable (Linux shell) for overriding the system-wide timezone (i.e. to use UTC instead).

The following is an example of how to modify the commands, if desired:

$ TZ=UTC faketime -f "2022-01-01 00:00:00" <command>

Where <command> would be gpg --expert --full-generate-key or similar.