I just finished reading a scifi book called Venemous Lumpsucker which had this type of system as a minor plot point. An interesting twist was that there were e

I just finished reading a scifi book called Venemous Lumpsucker which had this type of system as a minor plot point. An interesting twist was that there were essentially smart-contract based non-disclosure agreements that could effectively disable attestation for photos and videos on a specific device that had consented to the NDA.