GPG Details of Anatomy What is the "created" field below? How can you translate that into an actual date?



Source: https://davesteele.github.io/gpg/2014/09/20/anatomy-of-a-gpg-key/
It is a date that the creator of the signature chose to sign, usually representing the time at which the signature was created, in POSIX time, namely the approximate number of SI seconds that have elapsed on Earth's surface since January 1, 1972 at 00:00 in UTC, plus 63072000, minus the number of those that were labeled as leap seconds in UTC.

The Wikipedia article currently (2018-03-02) names January 1, 1970 at 00:00 in UTC as the reference point, but that must be interpreted as proleptic UTC because modern UTC, or just ‘UTC’ today, did not begin until 1972.  The OpenPGP standard, RFC 4880, §3.5 ‘Time fields’ makes the same mistake, and does not mention leap seconds, but basically all implementations agree to subtract the number of seconds that were labeled as leap seconds.

You can print a UTC representation of the same date and time given its POSIX time representation using the GNU coreutils date(1) utility as follows:


$ date -u --date=@1281838967
Sun Aug 15 02:22:47 UTC 2010