which is best Video Privacy App for Android?

i just got a new iPhone as my Wedding gift thanks to my friend but bit confused with how can i do privacy to some of my private images and videos. i don't have any idea about any good app for privacy protection in my phone but while research i found LEO Privacy Guard do any one have idea about hows it ? and will it be free or it will be chargeable ?

any other app idea is also welcome thanks