Encrypt Data
If you encrypt the data before you wipe your data the forensic guys will try to recover the deleted data, well they can try this, but what do they find? Right, encrypted data!
Go to Settings ->Security ->Encryption (Android Devices Has Different Settings Just Look For Encryption).
WARNING:
◾️If You Encrypt Your Phone, And You Cancel Or Interrupt The Process Your Lose Your Data!
◾️Charge Your Phone If You Encrypt It
◾️Device Must Be Unrooted
You gonna hit (if a button exists) “Encrypt Phone” and then is say for example “You can encrypt your accounts…” just hit “ENCRYPT PHONE”. The phone takes time to encrypt. If you maybe know, Encryption will take time so relax (normally it takes up to 1 hour. After this, backup your data (the encrypted one!).
Factory Reset & Wipe
You can factory reset your android device from the “Backup & Reset” > “Factory Data Reset” settings, or you are doing a recovery boot. For different devices the combinations are different. Just look on the internet “How to recovery boot Samsung s20”. For the advanced method, you gonna reboot into the recovery mode.
Once you are into the recovery you have the following options:
◾️Reboot system now
◾️Reboot to bootloader
◾️Apply update from ADB
◾️Apply update from SD card
◾️Wipe data/factory reset
◾️Wipe cache partition
On different devices, you have maybe other options like:
◾️Mount /system
◾️View recovery logs
◾️Run graphics test
and much more.
We are interested in to the last 2 features:
◾️Wipe data/factory reset
◾️Wipe cache partition
Wipe Cache partition is useful if people have problems and this would be a good error fix, you just clear all caches of the partition of your android device. The cache partition is a problem maker and if you wipe it you maybe have a better battery, more speed, and no errors, the cache just saves for example downloads from the play store, protocols, and recovered files. We just delete temporary data with the wipe cache partition option. I don’t want to talk much deeper in here just want to tell you what you are deleting and why.
Once you are into the recovery, you can navigate using your volume up and volume down and with the power button, you select an option.
First select “Wipe cache partition”, it is asking you if you want to wipe, go volume down and “YES”
Second select “Wipe data/factory reset”, it is asking you as well, and do “YES”. The reboot process could take time.
Well, you are done.
For the paranoid guys, there exists a method called zero filling. This method formats a hard disk and overwrites it with zeros(bit for bit).
You gonna wipe your data once, then you boot your phone, collect some data like random contacts, images, and reboot your device again and wipe again data. This process you are doing 3-5 times.
However, I hope you learned today a bit more about security and erasing data before you are selling your phones.
More about ZERO FILLING
