When importing your files in a protected folder, they are encrypted with a password hash and stored inside the app. The hash of the password is stored in the Keychain. What does all this mean?
It means that at no point of time the actual password is stored physically. Nobody can know it, except you! Moreover, the files inside the app are stored encrypted as well, so even if you lose your phone or it gets Jailbroken, by no means can someone open and view these files.
You can have an unlimited number of folders, protected with different passwords, inside other protected folders!
To further restrict anyone from accessing the contents of the app you can set a PIN protection.
Secure Files does not have a backup feature, it does not store your files in the cloud. This is intended, and, once you forget the PIN or the password for a certain folder - consider those files gone FOREVER!
By using the app you agree to the following Data Privacy: https://docs.google.com/document/d/1JscieYYg0Mar4UfKO7Gq1WrK9UQDm5RsnBs321nPr5s/
In case of questions, use the app's "Give Feedback" feature or contact me at firstname.lastname@example.org