Warning by CNET: iPhone "Restore" does not delete personal data!
Here is a small tutorial on how to delete, erase, wipe all personal data from iPhone permanently? Delete 17+ kinds of data: contacts, SMS text messages, call logs, photos, music, movies, apps, account information, passwords and more personal data stored on your iPhone 5S/5C/5/4S/4.
iPhone Data Eraser - Wipe iPhone Remotely, Delete iPhone Data Before Selling
> Permanently erase content from your iPhone 5S/5C/5/4S/4
> Works with all iOS Devices - Jailbroken iPhone friendly and also compatible with carrier-locked iPhones
iPhone: iPhone 5S, iPhone 5C, iPhone 5, iPhone 4S, iPhone 4
iPad: iPad Air, iPad mini, iPad with Retina Display, The new iPad, iPad 2, iPad 1
iPod touch: iPod touch 5, iPod touch 4