[cHalgan]

Hey... If you want to be secure that what you need to do. The keys must not be easily accessible.

Anyway application which need to be secure are not the one you also would like to be restarted automatically or unattended: automatically restart can in many cases just make situation worse (i.e., data corruption)

You can always pay big bucks and use Oracle Database with Transparent Data Encryption: in that case, you need to enter password to open the wallet only on startup of a database.