With eye-witness reports and photos taking such a prominent part in the recent middle-Eastern uprisings, Duke University scientists have found a way to guarantee their authenticity.
Their YouProve feature, which can be integrated into the Android OS, monitors images and audio captured with mobile devices.
It tracks changes made to files in third-party applications by recording edits that significantly alter the meaning of media, such as blurring a face in an image or inserting extra content. It also records changes that preserve the original meaning, such as reducing the resolution.
"With the Arab Spring and the Iranian protests in 2009, we relied on citizen journalists for information," says computer scientist Landon Cox.
"But as crowd-sourced content plays an increasingly important role in world affairs, falsified media could have severe consequences. It's important that we make sure the information we are getting is accurate."
With YouProve, Android keeps copies of images or audio clips that are opened in apps such as Facebook, Photoshop Express for Android or Garageband, and then tracks what the app does with the data.
If it writes a modified version of the media to a file on a phone or over a wireless network, YouProve uses advanced audio and image analysis algorithms to compare the original data to the modified one. It then produces a 'fidelity certificate', describing how much of the original data has been preserved.
With the user's consent, it then posts the fidelity certificate along with the edited media on the internet.
In tests, YouProve correctly identified edited regions of photos or audio clips with 99 percent accuracy, says the team.
Getting the system up and running, though, will require phone manufacturers to make their devices' trusted hardware accessible to the software. Cox says he is optimistic this will happen soon.