Page last updated at 17:03 GMT, Wednesday, 12 August 2009 18:03 UK

This website will self-destruct...

Digital Planet
By Dave Lee
BBC World Service

Destroyed hard drive
Physical destruction of hard drives may no longer be necessary

Read it quickly: this article will self-destruct in eight hours.

Not really, of course - but soon, permanently vanishing web correspondence could be the next step in maintaining your privacy online.

Emails, Facebook messages, and Google Docs can all be set to disappear into thin air by using new software developed by the University of Washington and called, appropriately enough, Vanish.

"We wanted to create a system that would allow our data to self-destruct and become permanently unreadable," assistant professor Yoshi Kohno, who designed the software, told the BBC's Digital Planet programme.

"[This would be for] both to ourselves and everyone else after a certain period of time."

Security solutions

With so much data now being created, shared, and stored online - rather on individual computers - documents could remain online for years, even after the user deleted the original file.

Using Vanish, however, means that even archived or backed-up copies of the data are unreadable after the time limit set by the original user.

Unlike other security solutions (many of which rely on passwords or data encryption) Vanish will make the document permanently unreadable to hackers and even law enforcement officers.

It works by creating a secret key which is split into small pieces and shared across many users on a peer-to-peer network. Over time, as users join and leave the network, the pieces of the key will disappear, rendering the data unreadable.

Vanish software
The Vanish software doesn't look much - but concerns have been raised

Peter Sommer, a digital forensics specialist at the London School of Economics, has concerns over possible misuses of the system.

He believes that the principles of security, privacy and online correspondence work alongside the same principles as police being able to enter a person's home and make arrests.

"I think it would be a bad thing because you have to recognise there are certain circumstances in which you do want the state to be able to carry out interceptions," he said.

Nefarious plans

Professor Kohno acknowledges that the software could be used for ill intent, but maintains that it would be a genuine technological advancement.

"When the automobile was first introduced there were jurisdictions that tried to outlaw the car because it allowed bank robbers to get away from the scene of the crime faster than the mounted police could catch them," he points out.

"In this particular scenario, I do believe that there are people who use Vanish to make data self-destruct that shouldn't be doing it. But the benefits far outweigh the risks."

Even with this new technology, professor Kohno maintains the key to better online safety and privacy ultimately lies with ourselves.

"My biggest recommendation is: just be sceptical. Having that perspective on new technologies will make you a much more informed consumer, and help you better control your privacy."

Digital Planet is broadcast on BBC World Service on Tuesday at 1232 GMT and repeated at 1632 GMT, 2032 GMT and on Wednesday at 0032 GMT.

You can listen online or download the podcast .

Print Sponsor

Confidential data 'not kept safe'
01 Jun 09 |  Glasgow, Lanarkshire and West
Personal data safety is discussed
28 Jan 08 |  Isle of Man
How to keep your wi-fi network safe
27 Apr 07 |  Technology
Slack security for old computers
03 Sep 04 |  Technology

The BBC is not responsible for the content of external internet sites

Has China's housing bubble burst?
How the world's oldest clove tree defied an empire
Why Royal Ballet principal Sergei Polunin quit


Americas Africa Europe Middle East South Asia Asia Pacific