I am selling an iPhone 5s which currently has iOS 7.0.4 on it. Before I sell the phone, I will be erasing its data contents. However, and please forgive my complete ignorance, since the phone is on iOS7, the buyer could jailbreak it. If the buyer jailbreaks the phone, would they have access to recovery software/apps to try to restore the data I had on the phone, or is this simply impossible, and not something to worry about? It's just a paranoid thought I had since I have never sold one of my used iPhones before. Thanks!