A team of University of Washington researchers released the first part of a public system that will authenticate video archives of interviews with prosecutors and other participants of the International Crime Tribunal for the Rwandan genocide. Initial portions of the Rwandan archive will also be unveiled, according to a report in the New York Times.

The system, whose digital technology will make it more difficult to misrepresent historical events in the future, seeks to digitally authenticate and preserve first-hand accounts of war crimes, genocide and other atrocities.

Such tools are of critical importance since it is now possible to digitally alter video, text, audio and other material in ways that are undetectable without the aid of technology.

The system is based on an algorithm that is used to compute a 128-character number, known as a cryptographic hash, from the digital information contained in the document.  Even the tiniest change in the original document will change the hash value.

Source