You recently sold your old smartphone and now strange things suddenly start happening: bills arrive for online purchases you never made and your acquaintances receive emails you never wrote.
In the worst case, your private photos might turn up on the internet.c To ensure this never happens, always delete all data thoroughly before selling or giving away a smartphone, tablet or computer.
"Many users are unaware that a lot of their personal data is stored on the phone," says Rainer Seidlitz, a data protection expert with TUV Sud, an agency in Germany that rates consumer products.
Information commonly found on a smartphone includes sensitive log-in data for email accounts or online shops, the addresses and telephone numbers of friends, and personal photos. If it's a work phone, important company data may also be stored in the memory.
None of this data should ever be allowed to fall into the hands of a third party.
The problem: the operating systems on smartphones generally don't include a capability to delete that memory and be sure it is empty.
Usually all you're allowed to do is reset the device to factory settings.
Although doing a factory settings reset is a step in the right direction, it doesn't mean that the data on the phone has been irretrievably deleted.
Deleting a file generally means only that the file has been removed from the table of contents in the memory and the space it occupies is available for overwriting, explains Germany's Federal Office for Information Security (BSI).
You cannot tell whether the file has actually been overwritten or not.
"There's software to recover such data," said Seidlitz. "What's only 'deleted' can be quite simply retrieved."
To be sure everything is thoroughly deleted you need to overwrite the memory several times.
With modern discs the BSI recommends overwriting "once to several times," whereas older hard drives of less than 80 gigabytes should be overwritten sevenfold.
There are programmes to do this, said Philip Heldt of the North Rhine Westphalia Consumer Central. For smartphones, this software can be found in app stores. Some versions need to be downloaded onto a computer. The phone is then connected to it by cable.
For those who don't want to spend any money, there's a do-it-yourself method, Seidlitz said.
First the phone is returned to factory settings, then the device's video camera is turned on and directed at the wall or the table top till the memory is full.
Often people forget to remove the SIM card when selling the phone or giving it away.
"This must be removed," advised Heldt. Even if disabled, the SIM card should not be allowed to fall into other people's hands.
For computers and hard drives, the same rules apply as for smartphones - always delete everything before passing on or throwing away the devices.
The BSI recommends using special deletion programmes or the Secure Erase function built into more and more hard drives and SSD memory. Free deletion programmes include "Darik's Boot and Nuke" and "Parted Magic."
The final and most radical way to ensure all personal data is removed is to physically destroy the hard drive or memory chip.
"Whoever wants to be completely sure should destroy the memory completely," said Seidlitz. This applies even if the device is never to be turned on again as the data can still persist in the memory.
There are a range of tools that can be used to do this, from the sledgehammer to the power drill. It's advised to wear safety goggles and gloves when doing so. Is it worth going to all this trouble?
It just needs one embarrassing photo from your youth to turn up years later and ruin a job interview, and you'll realise it matters.
Philip Heldt advises playing it safe: "There are plenty of stupid accidents that can happen."
Comments
Comments are closed.