The bits written on mass sorage that are deleted remain there and are just marked as free storage until they get overridden by another file, this is how datarecovery works.
Here, we have a similar case, where iOS hat a problem deleting the file from storage but managed to remove it from photos app index (storage is not marked as free, file could still be accessed if we had root file access but the link which pointed the photos app to the picture got removed). Now after some time, it can happen that the photo somehow gets detected (most likely as a safety measurement so that user don’t lose a picture if said link gets corrupted) and instead of deleting the file, de link gets repaired.
Yes, it should, but is mostly not done. But better approach is to use an encrypted filesystem like iOS and macOS(only with fileVault enabled) does. You can not recover encrypted data.
What happened here did not happen to phones that got wiped but only to phones where one logged logged off iCloud and logged into new iCloud account. Still the same encryption keys for filesystem.
There is no proof that it ever happened to a phone that was wiped completely.
Performing secure wipes reduces the lifetime of the storage device, if you sell a PC with removable storage device, it is better to just replace it with a new one for selling, and of course use fileVault on mac, bitlocker on windows and LUKS on linux (of course on linux there are more ways and LUKS is a partition and not a filesystem)
The bits written on mass sorage that are deleted remain there and are just marked as free storage until they get overridden by another file, this is how datarecovery works. Here, we have a similar case, where iOS hat a problem deleting the file from storage but managed to remove it from photos app index (storage is not marked as free, file could still be accessed if we had root file access but the link which pointed the photos app to the picture got removed). Now after some time, it can happen that the photo somehow gets detected (most likely as a safety measurement so that user don’t lose a picture if said link gets corrupted) and instead of deleting the file, de link gets repaired.
(Warning only a noob assumption)
Source: https://www.iphone-ticker.de/foto-panne-unter-ios-kein-fremdzugriff-aber-peinlich-fuer-apple-234979/
That’s not how it should work. A wipe should do a secure wipe either by writing random data to every bit or by doing a flash erase
It isn’t practical to do that on a per file basis but when the device changes ownership it is necessary
Yes, it should, but is mostly not done. But better approach is to use an encrypted filesystem like iOS and macOS(only with fileVault enabled) does. You can not recover encrypted data.
What happened here did not happen to phones that got wiped but only to phones where one logged logged off iCloud and logged into new iCloud account. Still the same encryption keys for filesystem.
There is no proof that it ever happened to a phone that was wiped completely.
Performing secure wipes reduces the lifetime of the storage device, if you sell a PC with removable storage device, it is better to just replace it with a new one for selling, and of course use fileVault on mac, bitlocker on windows and LUKS on linux (of course on linux there are more ways and LUKS is a partition and not a filesystem)