Scientists hid secret codes in light to combat video fakes

It's easier than ever to manipulate video footage to deceive the viewer and increasingly difficult for fact checkers to detect such manipulations. Cornell University scientists developed a new weapon in this ongoing arms race: software that codes a "watermark" into light fluctuations, which in turn can reveal when the footage has been tampered with. The researchers presented the breakthrough over the weekend at SIGGRAPH 2025 in Vancouver, British Columbia, and published a scientific paper in June in the journal ACM Transactions on Graphics.

“Video used to be treated as a source of truth, but that’s no longer an assumption we can make,” said co-author Abe Davis , of Cornell University, who first conceived of the idea. “Now you can pretty much create video of whatever you want. That c