Autostart delivers a passphrase you configure to open the key store automatically, so there is no prompting for a key store passphrase. Autostart mode does not impact scripts, but potentially gives unfettered access to encrypted data.
Autostart can be configured when you enable your database for encryption, by adding -Autostart {admin | user} to the PROUTIL ENABLEENCRYPTION command. You can change the autostart configuration with the PROUTIL EPOLICY MANAGE command at a later point in time.