Spymarks, Not Watermarks

There’s a sneaky new evolution of the “watermark”, let’s call it — the spymark. Spymark“Spymark” A watermark is a visible mark embedded in a physical or digital medium to verify authenticity or assert ownership. A spymark is a hidden signal that makes your work traceable without your knowledge or consent. Spymarking is sneaking onto the internet Google SynthID is a spymark that embeds secret hidden signals “imperceptible to humans” (Google’s own words) into images, audio, text, and video. This signal can encode database identifiers that map to your identity. Your user records, full name, IP addresses, date of birth, physical addresses, political party affiliation, and more. Google’s SynthID-Image paper reports that its SynthID-O variant can encode a 136-bit payload in a 512x512-pixel image. That is enough room for a 64-bit database identifier, with 72 bits left for error correction. SynthID was not the first spymark system designed, and it’s hardly the only one under active development. OpenAI and many other tech companies are developing these systems at scale. These companies claim spymarking can help identify AI-generated content, yet they’ve gone beyond simple watermarking and built in robust tracking mechanisms. Social media, content production tools, and smartphones may soon find themselves filled with spymarking algorithms that sneak these signals into everything you publish. For example, images can be invisibly altered in their frequency domain to carry tracking information such as database IDs linked to users: A smaller version of Mochi’s photo contains a real toy watermark: ID 173, encoded through subtle pixel changes. Compare the original and marked image, animate the amplified differences, and decode the ID from the PNG. The associated author and timestamp are fictional. Why give it a new name? “Watermark” has become a catchall for historical marks of authenticity, banknote security features, copyright overlays, and hidden tracking signals in our media. That last usage obscures the privacy risk that some forms of modern “watermarks” have become. Most people tire of the discourse on privacy. It’s complex, repetitive, and seems irrelevant to the typical day-to-day routine of the average citizen. We can’t keep explaining the technicalities behind statistical tracking tools each and every time we need to communicate these concepts to people and expect them to pay attention. “To speak the name is to control the thing.” — Ursula K. Le Guin, The Rule of Names With a simple change of terminology we can put the privacy concern up front, cementing this issue in the conversation forever: Spy- — clandestine surveillance, involuntary disclosure -mark — embedded signal Now we get to disambiguate friendly watermarks from concerning new technology while leveraging the familiar etymology.