Keeping a client's information secure must be every repair technician's primary concern. When making a repair, the technician must contractually ensure that the client's private information will not be shared in any way. It's the right thing to do, and it gives the client peace of mind that their sensitive information is contractually protected.
When working with hardware destined for a new user, previous user data must be erased entirely. If user data isn't wiped properly, it may be accessible even after a new operating system is installed.
Think of it this way: computer data operates like the information in a textbook. Every file is listed in the book's index. If you tear out the index, the information in the book doesn't go away. It just makes it harder to find. Re-installing an operating system works the same way: only the index is destroyed.
Proper hard disk wiping goes further than just deleting the index. Every bit of information on the disk is overwritten, turning readable binary sequences into nonsense. To continue with the book example, proper hard disk wiping would be like turning every letter in the book into an X. Now, not only has the index been discarded, but the actual text has been rendered meaningless.
Always use proven methods to erase hard drives.
Wiping user data from a smartphone or tablet works slightly differently. The basic mechanics are the same: deleting a file erases the indexed file path but not the content. Private user data can be found after the file is deleted. The difference is that many smartphones and tablets are encrypted.
When erasing data from an encrypted device, a technician needs only to destroy the key code that makes the data usable. Once the key is destroyed, all data will be unreadable, even though it hasn't been overwritten.
Easy solutions for entirely overwriting the contents of smartphones and tablets aren't available. Many smartphones and tablets may be "factory reset" or "hard reset." This process erases all user data by destroying the encryption key. If the device is encrypted, use the following pathways listed below:
Settings > General > Reset
- Since iOS 8, encryption is default.
Menu > Settings > Privacy > Factory Data Reset
- KitKat is not encrypted by default
- Lollipop is not encrypted by default, despite what Google had previously announced