The company bought 20 old Android phones on eBay and of course all were formatted by the old owner, but when using a software to recover data, more than 40,000 different photos were recovered, including There are no less sensitive photos and private data.
Specifically, from these 20 phones, Avast has regained:
Avast also said they have identified the identities of four former owners through recoverable data. To thoroughly remove this information, users need to perform data overwriting, then the old data actually disappears. Here, Avast does not forget " advertising " that avast! Their Anti-Theft has the information override function to erase data thoroughly on Android.
Avast's research also shows that iOS's machine format mechanism is safer than on Android. On the new models, when reformatting the device, the iOS operating system will delete the key used to decode the data in case when someone can recover the data, there is no way to decrypt it. On older iPhones and iPods, iOS also automatically implements a data override to ensure the safety of personal information.