Doxxing-Proof Authentic Digital Media

Abstract.  We can't trust the images and videos we see online anymore.  Recent generative AI improvements support the creation and modification of convincing digital media in quasi real time.  We live in an era where these fakes are routinely shared online for fun, profit, or other nefarious goals.  Fortunately, technologies exist to embed cryptographic signatures and watermarks in these digital assets, proving their origin.  The Coalition for Content Provenance and Authenticity (C2PA) specification has been adopted by many technology providers (e.g., Microsoft, Google, Adobe, Meta, and OpenAI), camera manufacturers (e.g., Sony, Canon, Leica), and news media organizations (e.g., BBC, CBC/Radio-Canada, AFP).  Major deployments have started in 2025 and are accelerating in 2026.  In high-risk contexts (conflict zones, protests, corruption reporting) creators might be reluctant to share certified images and videos for fear of retribution.  Is there a way to reconcile the need for authenticated assets and the privacy of their creators? The answer is yes!  In this talk, we'll explore cryptographic options to provide privacy to those who capture and share digital assets, enabling anonymous yet verifiable content.  We'll present an open-source prototype that augments the C2PA specification by using blind signatures and zero-knowledge proofs to hide the signer's identity.  These technologies offer the best of both worlds: enabling the public, reporters, and whistleblowers to share sensitive authentic digital media with strong privacy protections.

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