Photo File Vault App

I'm beginner in IOS development. I want to make a app that I can hide my files, photo or vides like a vault app does. What type of encryption and decryption i have to use. What are pros and cons make this type of application. What type of thing i need to care of.

Can anyone help me giving a very good resource , so that i can lean from scratch.

Thank You.

Photo File Vault App
 
 
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