Digital eraser
January 25, 2011
German researchers have finally released their much anticipated software that allows Internet users to choose an expiration date for photos published online.
Michael Backes, the software's creator and the chair for Information Security and Cryptography at Saarland University, said the software currently only expires pictures in the JPEG format and only runs on the Firefox browser, but other types of data and other browsers will soon follow.
The software, which became available on Monday, costs about seven euros ($10) for a three-month subscription.
How it works
The software encrypts the picture with an individual key and this key has an expiration date. The encrypted picture can then be uploaded to any website.
If someone wants to display the picture, they have to install a free Firefox add-on to their computer in order to request the key to decrypt the photo. If the key has expired by the time someone requests it, the picture will no longer be displayed. By default, the photo will still be online, however it will be completely unaccessible.
Even though the software currently only encrypts pictures, the principle works for all kinds of data.
"JPEG data is actually the most difficult data to work with," Backes said in an interview with Deutsche Welle.
"When files get compressed, for instance when uploading pictures to a social platform, the pictures look exactly the same to the human eye, but it's something completely different in a technological sense. We had to find encyrption measures that would survive the compression process."
As text files don't have to undergo compression, it is even easier to let text files expire.
Viktor Mayer-Schönberger, the author of "Delete - The Virtue of Forgetting in the Digital Age" is full of praise for the new software.
"Forgetting in the digital age has become difficult," he said in an interview with Deutsche Welle. "The real challenge we are facing is just emerging. But it's laudable that such an innovative program is coming from Germany. One can only applaud the software engineers from Saarbrücken."
It's still possible to copy pictures
Critics have claimed the software could not stop users from copying pictures before they elapse.
"You can't prevent the copying mechanism," Backes said. "If worst comes to worst someone takes a picture of the computer screen."
The so-called unencrypted moment where other users can copy pictures is definitely far from being ideal, Mayer-Schönberger said, adding that he didn't think it was a fatal flaw.
"The Internet is divided up among very few providers, maybe seven to eight big ones such as Google, Yahoo or Facebook, to name a few, where illegal copies of pictures could easily be removed," he said.
"I'd rather see problems when it comes to X-pire's single server where its keys are being synchronized. Hackers could potentially attack this single point. I assume that such possible weaknesses will be improved over time."
Backes added that data protectionists, private groups and even the industry would be very welcome to run their own servers.
The software developer also rebuffed critics who said it would be possible for X-pire users to see who and when someone requested to see their pictures - and how often.
The server sends out the key that unlocks the picture, and it's also the server who knows the IP address of the computer requesting the key. But a computer's IP address generally is displayed once it accesses other servers as well.
Mayer-Schönberger said X-pire's success will depend on different factors.
"The core question is: Is it trying to do too much? X-pire will only succeed if it is very easy to use and individuals understand that it's up to them to regain control over their data," he said.
"Of course it would be preferable if information aggregators online like Facebook would allow the user to set an expiration date when uploading pictures."
Author: Sarah Steffen
Editor: Cyrus Farivar