Returning to Bosnia, he went looking for the Muslim family of Hamed Celik, his Serbian wife's brother-in-law.

ECONOMIST: The Yugoslav war

But as Mr Celik outlines the possible applications for reversible data-hiding, it becomes obvious why preserving image integrity is so critical.

ECONOMIST: MONITOR

In 1992, as the fighting started, Celik's family had fled from the eastern Bosnian hamlet where it had been for generations.

ECONOMIST: The Yugoslav war

The embedding process begins by extracting and compressing some minor details of the image, explains Mehmet Celik of the University of Rochester.

ECONOMIST: MONITOR