Extending Expiration Date of an Already-Expired GPG Key

[Matthew Flaschen]

Robert L Cochran wrote:
> Thanks everyone for pointing this problem out to me. How do I fix it? I
> don't sign my emails that much but when I do I'd like a valid signature
> to show up. Clearly I'm doing something wrong.

The basic issue is that not all keyservers "know" about the update.  For
instance, pgp.mit.edu did not when I checked:

gpg --keyserver pgp.mit.edu --recv-keys C2C60518; gpg --list-keys C2C60518
gpg: requesting key C2C60518 from hkp server pgp.mit.edu
gpg: key C2C60518: "Robert L. Cochran (Greenbelt)
<cochranb at speakeasy.net>" not changed
gpg: Total number processed: 1
gpg:              unchanged: 1
pub   1024D/C2C60518 2008-01-19 [expired: 2009-01-18]
uid                  Robert L. Cochran (Greenbelt) <cochranb at speakeasy.net>

However, the server you used did:
gpg --keyserver subkeys.pgp.net --recv-keys C2C60518; gpg --list-keys
C2C60518
gpg: requesting key C2C60518 from hkp server subkeys.pgp.net
gpg: key C2C60518: "Robert L. Cochran (Greenbelt)
<cochranb at speakeasy.net>" 2 new signatures
gpg: 3 marginal(s) needed, 1 complete(s) needed, PGP trust model
gpg: depth: 0  valid:   1  signed:   0  trust: 0-, 0q, 0n, 0m, 0f, 1u
gpg: Total number processed: 1
gpg:         new signatures: 2
pub   1024D/C2C60518 2008-01-19 [expires: 2010-02-21]
uid                  Robert L. Cochran (Greenbelt) <cochranb at speakeasy.net>

This can be remedied by sending to the uninformed keyservers.
gpg --keyserver pgp.mit.edu --send-keys C2C60518
gpg: sending key C2C60518 to hkp server pgp.mit.edu

Then, we see pgp.mit.edu is now aware of the update.
gpg --keyserver pgp.mit.edu --recv-keys C2C60518; gpg --list-keys C2C60518
gpg: requesting key C2C60518 from hkp server pgp.mit.edu
gpg: key C2C60518: "Robert L. Cochran (Greenbelt)
<cochranb at speakeasy.net>" not changed
gpg: Total number processed: 1
gpg:              unchanged: 1
pub   1024D/C2C60518 2008-01-19 [expires: 2010-02-21]
uid                  Robert L. Cochran (Greenbelt) <cochranb at speakeasy.net

Of course, the key servers ordinarily share keys amongst themselves
every so often.  But a manual update can't hurt.

Matt Flaschen