What are the common practices to protect data on iPhone


The client is concerned about safety of the data application uses and stores locally on device (e.g. they want to prevent reading our data files even on jailbroken iPhones). So I wonder - what are the possible ways to ensure data safety on iPhone?

Edit: I'm thinking about 2 ways of storing data - a bunch of xml files (maximum size - about 1MB) or sqlite database. I'm more inclined to the 2nd variant but still not sure

You might want to check out this article - Protecting resources in iPhone and iPad apps. It talks about a scheme to encrypt app resources at build time, which can then be decrypted when needed by your app. Decryption happens in-memory so unprotected temporary files are not left on the filesystem. You can even load encrypted HTML, PDF & images straight into a UIWebView.

For transparency's sake: I wrote that article and it is hosted on my own website.