tag:gpgtools.tenderapp.com,2011-11-04:/discussions/feedback/2489-encryption-failed-unusable-public-keyGPGTools: Discussion 2017-08-07T17:14:09Ztag:gpgtools.tenderapp.com,2011-11-04:Comment/424373932017-04-26T16:10:44Z2017-04-26T16:10:44Zencryption failed, unusable public key<div><p>Hey Jon,</p>
<p>the error message that "encryption failed" due to an "unusable public key" can be caused by an expired subkey in your own key.</p>
<p>To find out, if your subkey is expired:</p>
<ol>
<li>double click your sec / pub key in GPG Keychain<br></li>
<li>navigate to the "Subkey" tab<br></li>
<li>check the validity field</li>
</ol>
<p>In case your subkey is expired, you can change the expiration date to a date in the future. Your key then should be working again. to test, restart mail.app and send yourself an encrypted and signed mail.</p>
<p>Don't forget to upload the updated key to the key server (if you want to use them or previously uploaded your public key) and share it among your friends.</p>
<p>Let me know if that worked,</p>
<p>Best regards,<br>
Steve</p></div>Stevetag:gpgtools.tenderapp.com,2011-11-04:Comment/424373932017-04-26T16:38:02Z2017-04-26T16:38:04Zencryption failed, unusable public key<div><p>Thank you Steve, it turns out that the public key for one of the recipients had expired. We have generated a new key and all is well. Thank you for your help!</p>
<p>-Jon Lee</p></div>Jontag:gpgtools.tenderapp.com,2011-11-04:Comment/424373932017-04-26T16:40:09Z2017-04-26T16:40:09Zencryption failed, unusable public key<div><p>Jon, please note that the old key can be made valid again by simply adjusting the expiry date (even if the key has expired).</p>
<p>So you may want to consider revoking the new key (upload the revoked version if you uploaded the new key to the key servers already).</p>
<p>Then change the expire date of the expired key and again if previously uploaded to the key servers, upload the updated version.</p></div>Steve