"Still, there are practical applications, Gaeta and Fridman said. This is a way of adding a packet of information to high-speed data unseen without interrupting

"Still, there are practical applications, Gaeta and Fridman said. This is a way of adding a packet of information to high-speed data unseen without interrupting the flow of information. But that may not be a good thing if used for computer viruses, Fridman conceded." Anyone have any idea what they're talking about here? How would that be possible? What exactly do they mean?