Jailbreak then restore iPhone 5?

Is it possible to jailbreak my iPhone 5, install app locker- lockdown pro then restore it & keep the said app?
Really want an app to lock individual apps on my phone,
invariably people get there hands on your phone & in this scenario I want my private stuff to remain private.
Not jus speaking of pics, I already hav that app. I mean for things like mail, txt, memos, notes.
Don't want to jailbreak my phone if there's an alternative.

It's not possible. Once you restore you will lose Cydia and anything you installed from Cydia. The less you have installed from Cydia the more reliable your phone will be. Installing a few tweaks from Cydia won't slow it down or crash your phone unless the tweaks are not compatible with what ever firmware you are running.