3 ms·

Largely true, although submitting timestamp hashes to the blockchain is probably the easiest bit. "Camera looking at a monitor": While that might be simpler in

Largely true, although submitting timestamp hashes to the blockchain is probably the easiest bit. "Camera looking at a monitor": While that might be simpler in some setups, it doesn’t really solve my main issue. I want the signal to permeate the entire scene, not just appear in the corner of a display or overlaid on the video. By projecting the challenge onto all visible surfaces, we create a physical environment that’s difficult to fake (since you’d have to convincingly generate or remove those patterns in real time). Air-gapping isn’t really the goal right now. Finally, we're need much finer granularity than 15 minutes! The point is to lower the generation time below what is achievable via generative model. Thank you for the comment, and I hope these clarifications are useful. It's a new concept, so please forgive the clumsiness with which I may be communicating it.

o11c 2y ago
"The blockchain" is just a wasteful way of doing things compared to the plain crypto. "Overlay the entire scene" doesn't actually appear to add any information-theoretic value compared to simply bounding the timestamp at which the video was made. Nothing either of us is talking about will actually prevent fakes (before the camera signs it), only constrain the time at which the fakes are made. Slower-than-real-time generation of fakes is still significantly inhibited by the fact that the hash sequence can be checked for continuity across long lengths of time whose bounds are verified using the other steps.
- PolieBotics 2y ago
  I’m using a blockchain because it’s currently the most practical Byzantine Fault Tolerant (BFT) network available for timestamping the Initialization Vector and final hash. If you prefer a web-of-trust or another cryptographic framework, feel free to use that instead. By projecting across the entire scene, we significantly increase the complexity of any real-time forgery attempt. A single display that barely interacts with the surroundings is comparatively easy to spoof and not particularly convenient to deploy. Of course, if you think that simpler setup is worth exploring, go ahead and experiment! Keep in mind, this method differs from merely signing an image. It creates an optical puzzle that reality solves faster than a simulation can. The physical interaction with the environment adds complexity that’s difficult to replicate artificially. I tried placing a display in front of the camera about a decade ago, but found that approach too “analytically solvable,” so it lost its appeal for robust authentication.

o11c 2y ago

"The blockchain" is just a wasteful way of doing things compared to the plain crypto. "Overlay the entire scene" doesn't actually appear to add any information-theoretic value compared to simply bounding the timestamp at which the video was made. Nothing either of us is talking about will actually prevent fakes (before the camera signs it), only constrain the time at which the fakes are made. Slower-than-real-time generation of fakes is still significantly inhibited by the fact that the hash sequence can be checked for continuity across long lengths of time whose bounds are verified using the other steps.

PolieBotics 2y ago
I’m using a blockchain because it’s currently the most practical Byzantine Fault Tolerant (BFT) network available for timestamping the Initialization Vector and final hash. If you prefer a web-of-trust or another cryptographic framework, feel free to use that instead. By projecting across the entire scene, we significantly increase the complexity of any real-time forgery attempt. A single display that barely interacts with the surroundings is comparatively easy to spoof and not particularly convenient to deploy. Of course, if you think that simpler setup is worth exploring, go ahead and experiment! Keep in mind, this method differs from merely signing an image. It creates an optical puzzle that reality solves faster than a simulation can. The physical interaction with the environment adds complexity that’s difficult to replicate artificially. I tried placing a display in front of the camera about a decade ago, but found that approach too “analytically solvable,” so it lost its appeal for robust authentication.