Key expires at ... 1971

David Shaw dshaw at
Wed Jun 4 23:30:22 CEST 2008

On Wed, Jun 04, 2008 at 11:17:12PM +0200, Werner Koch wrote:
> On Wed,  4 Jun 2008 21:31, dshaw at said:
> > It's a bug.  OpenPGP has some date limits (there is a Y2106 issue
> > inherent in the protocol), but it should be able to handle expiration
> > dates up to 2242.  I'll take a look at it.
> 2242: I don't think so as we are using a 32 bit type almost everywhere
> in gpg.

Expiration dates in OpenPGP are calculated as the offset from the key
creation time, not 1970.  Only the key creation time is calculated
from 1970.  Both are 32-bit values, so the maximum expiration is
4294967295 seconds + 4294967295 seconds == 272 years.  Leaving out
leap years for simplicity, 1970 + 272 == 2242.

GPG has the limitation of treating an expiration time as an absolute,
rather than a relative offset from the key creation time, but this is
not an OpenPGP issue.


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