We can remove data permanently from android flash memory, which is encrypted, after a factory reset.

After doing this, do we need to decrypt the device for using it again or factory reset the device?


2 Answers 2


It is in the default factory reset state ( like a new device ). You can't decrypt the device even if you wish to as the encryption password (generated from a combination of user lock screen PIN and encryption algorithm ) is lost

From Android's Factory Reset Does Not Wipe Your Data: Here's The Solution

Encrypting does not completely delete the files, but the factory reset process gets rid of the encryption key. As a result, the device has no way it can decrypt the files and, therefore, makes data recovery extremely difficult.

  • No i don't want to use as encryption device i want to clean data permanently from device.So i have read the solution that if i make encryption in my device and after encryption do the factory reset my device will go to its default setting is it true?After doing this can i sale my device with privacy trust?
    – sad
    Mar 31, 2017 at 2:20
  • Yes. You are right. 1. The device will be in factory reset state like when you bought the device and took it out of the box 2. No one can access your files since encryption key is not available 3. Your privacy is secure. If the answer, meets your expectations please tick the green arrow next to answer ( since you don't have reputation to upvote) . There is no obligation - ticking it means that the answer is accepted
    – beeshyams
    Mar 31, 2017 at 3:05
  • I'm login into my mobile using PIN and my phone is decrypted successfully after that i started factory reset now my all data erased as well as encryption key. My question is when i start factory reset my data will be encrypted or not ? Because after login into my phone my data is already in decrypted form so factory reset meaning wiping data in form of decrypted format not in encrypted . @beeshyams May 28, 2020 at 6:28
  • @MuhammadFaizanFareed Data stays encrypted, after factory reset, the key is lost, that's why the device treats it as unencrypted and prompts you to encrypt again
    – beeshyams
    May 28, 2020 at 6:37
  • 1
    @MuhammadFaizanFareed yes, if it was encrypted before. If this is not clear, I suggest you make a fresh question, quoting this and explain the complete situation clearly with your doubt
    – beeshyams
    May 28, 2020 at 7:05

When the device is encrypted, the decryption key is only known by the current OS.

If you know the pin (for that screen you get before the animation starts), the device can be decrypted and get booted up successfully.

If you don't remember that, then you will need to reset the device. This resetting is similar to a factory reset.

Factory reset will not retain your personal data and apps in the internal storage.

Your external (micro) SD card, if present, can be removed before doing the reset only if it is configured as a portable storage in Android.

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