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C2PA's Double-Edged Sword: From Technical Expert to Expert Witness

Last year, I worked with the TRUE Project and the Institute for International Legal and Advocacy Training (IILAT) to develop training materials and legal arguments – an experience that shifted how I think about the intersection of technology and justice. The work has (hopefully!) led me toward expert witness roles, and I’m continuing the collaboration with IILAT on a second round of training at the Inner Temple in July 2025.

From Behind the Scenes to… the Witness Stand?

Yvonne McDermott, from Swansea University and the TRUE Project, asked me to participate to the development of their September 2024 advocacy training, to take place at IILAT in The Hague. I pitched to the design of their comprehensive scenario, and to competing expert analyses designed to stress-test how participant lawyers might interrogate digital evidence in an era of deepfakes, AI-generated content, and sophisticated misinformation campaigns. I notably focused on emerging standards like C2PA and their implications for both prosecution and defence arguments.

I felt participants should grapple with emerging technical standards like the Coalition for Content Provenance and Authenticity (C2PA). Through the work of a fictional “Truth Crews” organisation, who provided verification in a classic OSI / user-generated evidence scenario, I explored both the promise and the peril of cryptographically signed metadata.

The provenance question, asked about a C2PA example, proved particularly complex. The emerging standard promises to revolutionise digital evidence by embedding cryptographically signed metadata that can trace a piece of content from creation through every modification. On one hand, C2PA might offer unprecedented transparency: prosecutors could present media with verifiable chains of custody, timestamps that can’t be easily manipulated, and attestations from trusted organisations. On its face, all sounds great, doesn’t it?

On the other hand, the defence concerns are equally compelling: the very legitimacy that C2PA provides could become a weapon. When content bears the digital signatures of reputable software like Adobe’s or verification from established organisations, courts might give it undue weight – even when the underlying content itself remains unverified. The green checkmarks and corporate logos could create what I termed a “veneer of legitimacy” that makes sophisticated forgeries more convincing than crude ones ever were.

I found myself grappling with these very questions: How do we distinguish between reliable open source investigation and proper forensic examination? When does corroboration become meaningless in the face of scale manipulation? Do emerging verification technologies change the game entirely?

Building Bridges Between Technology and Justice

On the need for this dual role – expert witness and training designer –, I’ll report back after engaging with the other trainers and participants in July. I certainly think that there’s a need for professionals who can translate complex technical concepts for legal audiences while understanding the practical constraints and requirements of judicial proceedings and digital investigations. But being in this situation, I would think that, wouldn’t I.

So I hope that the collaboration between Starling Lab, TRUE Project, IILAT, and institutions like the Inner Temple represents exactly the kind of cross-disciplinary work we need more of. By bringing together technologists, legal practitioners, and judicial institutions, we’re building the expertise necessary to navigate an increasingly complex evidence landscape.