For a few days, we have seen many subjects on the web that insist on the insufficient nature of the restoration of the phone under Android to delete personal data.The information follows a discovery made by the teams of the famous Avast antivirus who managed to recover tens of thousands of photos, SMS or email on 20 used smartphones however erased.However, there are secure ways to erase your data.

This is a pavement in the pond that Avast threw a few days ago by announcing that he had managed to recover more than 40,000 photos, 750 emails and sms as well as 250 contacts on used Android terminals.These smartphones had however been given in their original state with a restoration.This discovery of Avast is not really one since we could expect such operation, similar on PCs.In fact, when the user makes a restoration, Android is content to erase the list of files in the partition.But the data continues to be readable with certain software methods since it still exists on flash memory.The principle is the same on a computer: if you just delete files, they will remain accessible with specialized data recovery software that is found for free on the Internet.

The risk on privacy

The market for smartphones occasion is highly prized since consumers regularly renew their aircraft by reselling the old ones on eBay or Leboncoin.I am sure you would not like your phone buyer to find your personal photos, contacts, emails or files that you would have scanned like a lease, an employment contract or identity documents.There is therefore a solution so that the buyer does not have the possibility of recovering your personal data and thus protecting your privacy.

The solution: reset flash memory

The solution is therefore to erase once for all this data by putting back in their original state each cell of flash memory composing the phones storage space.

For the small explanation, a flash memory cell has two possible electrical states which are materialized under Android by a 0 or a 1 (binary system).If each cell is reset, then it will be impossible to recover the data since it will no longer exist at the material level.On PCs, formatting is a simple and effective method, but under Android, there is no tool in this way.There are then two different solutions that can be complementary.

Solution 1: data encryption and filling

The first solution proposed by CNET is the simplest to implement.It consists in encrypting data from its Android terminal before erasing it.In this way, even if it is possible to recover the data, it will take a key to be able to read it.It is therefore not the safest method since there are solutions (very complicated) to use to read this data.But it should be impossible to recover all this with simple data recovery software.It is also possible to carry out this operation even if you do not plan to resell your phone, but to prevent a flight or a loss.

So you have to go to phone settings, security, then press the phone quantify.The operation will take some time, depending on the amount of data you will have to quantify.Once the encryption has been made, you can restore the phone.The site also recommends, once the catering has been carried out, to load non -sensitive data on the phone to rewrite those which would still be present at the material level.It is then enough to transfer photos without interest for example, until filling out the phone.Then it will be necessary to restore the phone again.

Solution 2: Random filling

Another method exists and it is a little more complex to implement and rather reserved for experienced users.It takes up the principle of filling the phone, but this time with a Rooté phone, Busybox installed and the Android SDK on a computer.The SDK will allow random data to the telephone in the directories /sdcard and /data that contain the personal data of the user.

The operation is automated (as long as the right command lines are hit) and therefore allows you to fill the phone without using personal files.If you are interested in this solution, you can consult the very good article (in English) of Zackery Fretty, an Android developer.Once you have carried out this operation, a simple restoration will suffice.This method should be as effective as that of CNET, without the need for encryption.

Now you have warned: if you have a little sensitive personal data on a phone, remember to make one of the two methods to really delete files from Flash memory of your device under Android under Android.There is little chance that the buyer of your aircraft will have a hit or getdataback, but you are never too careful!

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