[brippalcharrid]

Cryptographically verified recordings don't sound practical to me (sensors and video processing electronics sound like a lot of hardware to put in a secure element), but I'm sure we will see generative AI inflating away the value of blackmail material soon; one mitigation for this could be cryptographically signing material and then publishing the signature long before it becomes practical to fake it (i.e. the past, increasingly), then periodically creating signatures with new algorithms in advance of the discovery of practical attacks on existing ones.

[luma]

The only thing that'd need to be in a secure element would be the signing keys. This has existed for a while for digital cameras. Canon, Nikon, and Sony have all brought still image solutions to market for use in situations like photojournalism or forensic evidence collection.

[munk-a]

Device signing can be used very effectively to tell if a particular devices was involved in an action - but it is far more difficult to tell if some non-specific device was the source or whether it was generated. When it comes to fabricated video evidence we'd need to establish a circle of trust that included every camera ever produced but was somehow secure and unforgeable. We've seen this approach break down previously with Diginotar[1] - it really only takes on weak link in the system to compromise the verification. At the scale with which cameras are demanded it seems unreasonable to expect a centralized signing administration to be able to keep their tokens all completely secured.

1. https://en.wikipedia.org/wiki/DigiNotar

[brippalcharrid]

I don't think that the signer would be able to verify the authenticity of the data that it received from the sensor and image processing circuitry unless they were able to authenticate each other securely. I know that an attack on a system like you proposed would still be expensive, but it would become more attractive if its characteristics were overplayed (and would then be subject to legal challenge). Forensics, of course on the other hand is based on experts saying "yes, by all accounts this appears to have happened".