Trying to understand better GPG and how to manage my keys

john2x · 10-27-2018, 02:50 AM

I want to better understand how to use GPG. I want to keep things simple by only using 1 key pair (so no sub-keys for now).

My question is about updating the expiry of a key. When I update the expiry, do I need to generate new public key, new backup, and new revocation certificate? And for the public key, I should re-share it with anyone I previously shared with and/or re-upload to the public key server?

Thanks in advance.

berndbausch · 10-28-2018, 01:42 AM

To be honest, I don't know that much about keys, PKI, GPG etc, but it seems to me that there are no side-effects when you change the expiration date. I.e. all that changes is the date - the key remains the same, any certificates as well.

See also the documentation for the gpg management options. Generally, GPG guides, including the GPG handbook, look quite useful.

ntubski · 10-28-2018, 07:16 AM

https://www.gnupg.org/gph/en/manual.html#AEN329

Quote:

Updating a key's expiration time

The expiration time of a key may be updated with the command expire from the key edit menu. If no key is selected the expiration time of the primary key is updated. Otherwise the expiration time of the selected subordinate key is updated.

A key's expiration time is associated with the key's self-signature. The expiration time is updated by deleting the old self-signature and adding a new self-signature. Since correspondents will not have deleted the old self-signature, they will see an additional self-signature on the key when they update their copy of your key. The latest self-signature takes precedence, however, so all correspondents will unambiguously know the expiration times of your keys.