Head to the Settings app, and under Security, you’ll see a few settings for device encryption. If you’ve got an expansion slot, your device might also offer you the option to encrypt the inside SD card. Still, you don’t need to worry about that if you pop it out and keep it for yourself. The device will take a while to encrypt, depending on how much data you have. Often up to an hour. But when you’re all done, you can perform that factory reset. Knowing that your information is technically still in all the blank areas of your phone’s storage. It’s encrypted and can’t be easily read.
