California SB 942: the AI Transparency Act
Definition: California SB 942, the AI Transparency Act, requires covered generative AI providers to make AI-generated content detectable through disclosure and provenance, with the operative date realigned to 2 August 2026 by AB 853.
TL;DR: SB 942 applies to GenAI providers with more than 1 million monthly users in California. It requires a latent disclosure in AI output and a public detection tool. AB 853, signed 13 October 2025, moved the operative date to 2 August 2026, aligning it with the EU AI Act. Penalty: $5,000 per violation per day.
What SB 942 requires
Covered providers must embed a latent, machine-readable disclosure in generated content and offer a free public tool to detect whether content came from their system. The law leans on provenance and watermarking as the mechanism, which maps cleanly to a signed manifest plus a watermark.
Who is covered, and when
The threshold is more than 1 million monthly users in California. AB 853, signed 13 October 2025, realigned the operative date to 2 August 2026 so providers face one effective date across California and the EU. That alignment is a planning gift: build once, satisfy both.
How to comply with one pipeline
Mark output at generation with a C2PA assertion and a watermark, expose a detection endpoint, and keep the disclosure latent so it survives normal handling. The same POST /v1/sign call that satisfies Article 50 produces the marked asset SB 942 expects.
The incident behind this
AI-generated political advertising in California's 2024 cycle pushed the state toward stricter transparency rules, and SB 942 with AB 853 is the result aimed squarely at large generative providers.
Implementation
curl -X POST https://api.originalpictures.com/v1/sign \ -H "Authorization: Bearer $OP_KEY" \ -F "[email protected]" \ -F "disclosure=ca.sb942" \ -F "watermark=trustmark"
Regulatory mapping
| Regime | Effective | Bite | Why it applies |
|---|---|---|---|
| California SB 942 / AB 853 | 2 Aug 2026 | $5,000 per violation per day | GenAI providers >1M CA users |
FAQ
Does SB 942 overlap with the EU AI Act?
Yes, by design after AB 853. The same marking pipeline addresses both effective on 2 August 2026, though disclosures and tooling differ in detail.
Where Original Pictures stands today
Original Pictures ships three things today: a Sign API, a Verify API, and the SDKs that wrap them. One POST /v1/sign attaches a C2PA-format manifest, an invisible TrustMark watermark, and an OpenTimestamps anchor. The open-source verifier checks any of it without calling us.
Two things are on the near roadmap, and we name them as roadmap, not as shipped: C2PA Conformance Program recognition (target Q3 2026, until then our manifests use the published C2PA v2.2 format and any C2PA-aware validator can read them, but third-party validators will show our signer as not-yet-listed), and a consumer capture app (Q3 2026). We do not sell a capture SDK, and we do not claim Trust-List membership we do not yet hold.
Bottom line: SB 942 lands the same day as Article 50. Build one marking and disclosure pipeline, expose a detection tool, and you cover both California and the EU.
Related
Original Pictures is progressing through the C2PA Conformance Program; our signing certificate is not yet on the official C2PA Trust List. Target: Q3 2026. We will not describe ourselves as "C2PA-certified" until it is true.
Original Pictures provides content-provenance infrastructure. It does not by itself constitute legal compliance with the EU AI Act or any other regime; compliance depends on how you deploy it, your disclosures, and your governance. Figures are drawn from public reporting, verify against primary sources before citing in regulated materials. Nothing here is legal advice.
Last verified 2026-05-25. Author: Mahdi Kazempour, Founder, Original Pictures.