Securely erasing personal data from Android phone before selling

Factory resets reset your phone to a stock like state but does not remove your data, just applications. This leaves some data behind. The best way to prevent this data from being recovered is to encrypt the phone, and use wipe data/factory reset from the recovery menu. This way you don't have to download a ton of data and you can be fairly certain your things are secure.

If you're not that worried, encrypting, and data/factory reset from the recovery menu is probably enough.

EDIT: Whoops forgot to mention why the recovery mode data/factory reset. It formats the user data areas as well as the application area, and is far more thorough/secure than the one inside of the android OS and will prevent you from download junk data. It just flat out gets rid of it.

To get to the recovery console on the Nexus 5 for resetting:

  1. If your phone is on, turn it off.

  2. Press and hold the Volume Down and Volume Up buttons, and then press and hold the Power button at the same time until the phone turns on. You'll see the word "Start" with an arrow around it.

  3. Press the Volume Down button twice to highlight "Recovery."

  4. Press the Power button to start Recovery mode. You'll see an image of an Android robot with a red exclamation mark and the words "No command."

  5. While holding the Power button, press and release the Volume Up button once.

  6. Press the Volume Down button twice to highlight "wipe data/factory reset" and press the Power button to select it.

  7. Press the Volume Down button seven times to highlight "Yes - erase all user data" and press the Power button to select it.

  8. After the reset is complete, press the Power button to select the option to reboot your device.


Usually Factory Reset is probably enough for removing almost all data stored internally by the Android phone.
Menu> Settings> Privacy> Factory data reset> Erase phone storage
Un-tick backup if not necessary.

To be double sure(Extra paranoid mode):

  1. Do the Factory reset and then Menu> Settings> Security> Encrypt phone> Encrypt phone(read the description)
  2. Now download random data from internet, like images, music, files, programs etc till device memory is filled to 100%.
  3. When the phone memory is full, redo factory reset again.

A tool I found (free) is iShredder

Some related already asked questions:
how-do-i-delete-all-data-from-my-android-phone
i-have-sold-my-phone-on-ebay-what-should-i-do-before-i-send-it-off

This assumes external SD card is not transferred with the device.

Tags:

Mobile

Android

Data Recovery

Data Leakage

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