One time I internet searched the term “steganography”, thinking it was the study of where dinosaurs lived, but discovered it is actually the practice of hiding secret information inside a non-secret message. There are three qualities of a good steganography approach: imperceptibility, robustness, and embedding capacity. I thought to myself, that sounds like dope spy stuff and I definitely want to do that. It turns out video can be a fantastic non-secret message format in which to conceal covert messages. There are a few common approaches to make data undetectable, including bit manipulation ie the Least Significant Bit algorithm, as well as exploitation of alpha channels, pixel padding, and metadata. Oh and there is this cool cryptographic concept of secret sharing, which can be used in video steganography to ensure the message is retrievable, even if some of the secret bits are missing. And embedding capacity is almost a given, as video files are often large and compressed. This talk will go more in depth into how these methods work but don’t worry, the scary LSB and secret sharing maths will be softened with jokes and gifs. Finally, the stretch goal for this spy talk is to encode secret data into a real-time media stream using the WebCodecs API. Early experiments have been less than promising, but I am not yet deterred. Even if real-time video steganography is not achieved, after this talk we can say we know a lot more about this fascinating concept and it is probably more useful than knowledge about dinosaurs*.

*dinosaur gifs are likely, but not promised. This talk was presented at Demuxed ’23, a conference for video nerds in San Francisco featuring amazing talks like this one.