Secure contents in Documents directory

Question

Can anyone help me to make the contents of my Documents directory secure?

Answer 1

Use:

- (BOOL)writeToFile:(NSString *)path options:(NSDataWritingOptions)mask error:(NSError **)errorPtr

with one of the file protection options:

NSDataWritingFileProtectionComplete (iOS 4.0)
NSDataWritingFileProtectionCompleteUnlessOpen (iOS 5.0)
NSDataWritingFileProtectionCompleteUntilFirstUserAuthentication (iOS 5.0)

See: Apple Documentation

NSDataWritingFileProtectionComplete

In this case, the file is stored in an encrypted format and may be read from or written to only while the device is unlocked. At all other times, attempts to read and write the file result in failure.

Note: Doing your own encryption raises the problem of key storage and the best answer there is to use the Keychain. Key handling is the biggest problem and the NSData methods handle that.

Answer 2

We cannot secure the file in documents directory. We can store the file in temp folder of the device. This cannot be accessed by anyone