Comment 5 for bug 238954

Upstream won't change the behaviour, as outlined in the paste below.

Upstream comment:

 Comment #1 from Adam Schreiber (seahorse developer, points: 19)
2008-08-28 16:47 UTC [reply]

You could store the passphrase securely in gnome-keyring. You would have to
enter it manually once and then it would be provided automatically in the
future.

Go to System -> Preferences -> Encryption and Keyrings

On the PGP Passphrases tab, select Always remember passphrases whenever logged
in and additionally if you want to be asked before it's provided check the box
next to Ask me before using a cached passphrase.