What features should be there in an good photo,video locking and hiding app?

[iMore Question]

What are the features you always wanted form a Photo,Video locking app for Iphone and Ipad?

I for one is most concerned about the security of my personal photos, let's say my phone got stolen and in that case will my safe app be able to keep the hackers or intruders away from my personal saved data?

Let me know your opinions.