Picture a courtroom scene that has played out for centuries: a prosecutor holds up a manila envelope, opens it to reveal a piece of physical evidence, and points to the chain of custody log — every signature, every handoff, every storage location documented in sequence. The evidence is authenticated. It is admitted.
That model served the legal system well for a long time. But in the fourth installment of the Concernant les preuves colonne dans Associé gérant d'aujourd'hui, PDG et fondateur d'iDS Dan Regard makes a compelling argument: for digital evidence, chain of custody has become the wrong question entirely.
Why Digital Integrity Is Now Trivial
When a digital file is collected, forensic software generates a hash value — a unique mathematical fingerprint derived from the file’s exact contents. If even a single bit changes, the hash changes. Re-run the algorithm at any point and compare the values: a match means the file is untouched.
No paperwork. No signatures. No reliance on human process or memory. Just math.
For this reason, Regard argues, proving the integrity of a digital file is now a de minimis exercise. Chain of custody for digital assets is still good practice and still part of the forensic process — but it is no longer where effort and expertise should be concentrated.
The Real Challenge: Proof of Origin
In an era of deepfakes, altered documents, and AI-generated synthetic media, the question courts are increasingly asking isn’t “was this file handled correctly?” It is “was this file ever real?”
That shift demands a new standard — what Regard calls proof of origin: the ability to confirm not just that a file is intact, but that it is genuine, that it came from the source it claims, and that it has not been fabricated from scratch.
Every digital artifact leaves a trail. Emails have headers. Documents carry metadata. Photos and videos contain embedded timestamps, GPS coordinates, and device signatures. The forensic task is to read those trails and answer deeper questions: Where did this file originate? Who created it? Was it modified, by whom, and when? Is this video a genuine security recording, or was it AI-generated?
A Practical Example
Regard illustrates the distinction through a criminal trial scenario where the key evidence is security camera footage placing a suspect at a crime scene. The defence argues the footage is fake — never actually recorded by the surveillance system at all. A hash check is useless here because the dispute isn’t about whether the file changed after collection. It’s about whether it was ever authentic.
Proof of origin techniques address exactly that: analysing metadata to confirm whether the file was recorded by the claimed system, checking embedded device signatures, cross-referencing security system logs, and applying forensic AI tools to detect frame inconsistencies or signs of manipulation.
A Broader Implication
Regard closes with a thought worth sitting with: the principles behind proof of origin are increasingly applicable beyond digital evidence entirely. In a world where physical objects are created, controlled, and recorded by computerised systems, the same data trails that verify a digital file can be applied to verify objects, events, and even testimony in ways that were simply not possible twenty years ago.
At iDS, staying ahead of exactly this kind of shift is central to how we work. Our Médecine légale numérique, Enquêtes, et Témoignage practices are built around the emerging standards of authenticity that courts are beginning to demand — not just the procedural ones they have always required.
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