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开发者_JAVA技巧 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.

Any time code is running on physical hardware that's out of your control, it is vulnerable - the iPhone must have the ability to decode the data for it to be usable, and if the iPhone has that ability, so does the user. If the data is valuable enough, someone will break your encryption.

The movie industry spent millions on their DVD DRM. It got cracked in a few weeks.

The commoncrypto library, available on the phone, supports symmetric encryption. You can store the key in the keychain, which is itself asymmetrically encrypted. The key to decrypt the keychain is baked into the hardware so you'd need to go to some lengths to retrieve the data.

(e.g. they want to prevent reading our data files even on jailbroken iPhones). you may use localytics mobile analytics(open source) to find out whether the application has been used in Jail broken iphone or not.. They have premium options also..Lot of mobile analytics are available.you can check..