iOS hardware-based encryption

I'm re开发者_开发百科ading this security PDF from Apple. On page 3 it talks about hardware level encryption. Does anyone have additional information on this? If I have custom applications on my iPad does this mean that any data stored within those applications will be encrypted and secured? So if someone stole my iPad, was able to hook it up to a computer or try to jailbreak it or whatever ... they couldn't get to that data?

On page 5 it mentions that developers can use API's to encrypt information for added security. Is this even necessary?

I'm writing a custom iPad application for ad-hoc distribution that will have some PDF files and video files within the application. The PDF files and video are confidential. If the iPad is stolen I cannot have anyone getting to that data. Will it be secure enough with the default encryption?

It's not an automatic process. You as a developer have to make sure to enable protection for all files you save. You also have to make sure that your app will not try to access protected files while the device is locked. See Working with Protected Files in the iOS Programming Guide for details.

Also note that data protection is only available on iPads that have gotten a fresh install of iOS 4.2. Devices that have been upgraded from iOS 3.2 need to be restored for data protection to work (source).