Mobile phone photos and text messages have come back to life, but why can deleted data be recovered?

Popular Science Times reporter Chen Jie

The iteration speed of mobile phones is accelerating day by day, and people are changing their phones frequently. Recently, the online topic "The old phone you sell may betray you" has become a hot search, which has aroused people's concern about the security of mobile phone data and their concerns about whether to keep or discard mobile phones.

Data shows that by 2022, my country will have eliminated as many as 500 million mobile phones. However, according to the Regulations on the Recycling and Treatment of Waste Electrical and Electronic Products, the recycling of waste electronic products must implement a qualification licensing system. But in reality, there are stores and small workshops that are not qualified for recycling everywhere. If you sell your second-hand mobile phone to them, the "deleted" data on the phone will be in danger. A reporter once experienced it on the spot. In just 20 minutes, the deleted application cache, photo album, call log, text messages and other information in the mobile phone were "revived", which makes people sigh that selling an old mobile phone is almost equivalent to "selling your privacy."

"Deleting data on a mobile phone does not completely erase the data from the phone's storage medium, but the system marks the space storing the data as overwritable," said Shen Zhe, a network technology expert, in an interview with Science Popularization Times. Before new data is written into these spaces, the deleted data still physically exists in the storage space. These seemingly deleted data can be recovered through specific data recovery software or technology.

So, how do we safely dispose of the data on old phones?

Shen Zhe said that when we want to delete personal data on our phones, we can repeatedly store some useless large files or videos in the phone and then delete them. "This method can overwrite the previous data storage location with useless data multiple times, which can effectively reduce the possibility of data recovery. But it should be noted that this method is not 100% effective, because even if it is overwritten multiple times, some data will inevitably slip through the net, and there is no guarantee that the deleted data will not be recovered."

What should we do with our old mobile phones?

Shen Zhe said that a safer approach is to restore the phone to factory settings and then hand it over to a regular second-hand recycling platform, e-commerce platform or phone manufacturer. "They all have strict procedures, and they will professionally clear the phone's data and carry out environmentally friendly treatment, which can realize the resource reuse of old phones."