How to encrypt Jelly Bean and KitKat devices
Step 1: Plug in your device’s power cable and allow the battery to charge. Keep the power cable connected.
Tip: The encryption process can take as long as 30 minutes or more. If your battery dies and the phone shuts off in the middle of the process, the process will fail, and you’ll lose data.
Step 2: Open the device’s Settings and look for the Security menu item. Then select the Screen Lock menu item and choose a PIN or Password and follow the prompts to confirm it.
Tip: One annoyance with encryption is that you’ll always need to enter a PIN, or the longer password, to open the device. Longer passwords are harder to hack.
Step 3: Scroll to the Encrypt phone or Encrypt tablet option within the Security settings and choose the Encrypt SD card option by checking the checkbox. Select Next and confirm your PIN at the prompts.
Step 4: Press the Encrypt phone or Encrypt tablet button.
Tip: You can’t reverse encryption in Android. If you decide to decrypt your device later, you’ll need to perform a factory reset, which will wipe all data.
Step 5: Just wait awhile. The device will reboot several times during the encryption process, which can take 30 minutes or more. On completion, you’ll be prompted to enter your password, which is your PIN or password, depending on what you’re using. Whatever you do, don’t forget it!