Many people believe that pressing the 'delete' button will make their data go away. 'The reality is that many web services archive data indefinitely, well after you've pressed delete,' Geambasu said.

Simply encrypting the data can be risky in the long term, the researchers say. The data can be exposed years later, for example, by legal actions that force an individual or company to reveal the encryption key.

'In today's world, private information is scattered all over the internet, and we can't control the lifetime of that data,' said Levy.

'And as we transition to a future based on cloud computing, where enormous, anonymous data centres run the vast majority of our applications and store nearly all of our data, we will lose even more control.'

Researchers compare using Vanish to writing a message in the sand at low tide, where it can be read for only a few hours before the tide comes in and permanently washes it away.

Erasing the data doesn't require any special action by the sender, the recipient or any third party service.

A paper about the project went public on Tuesday and will be presented at the Usenix Security Symposium Aug 10-14 in Montreal, Canada.