Digital chain of custody: from an award-winning paper to practice

My team and I won the Decentralized Governance LegalThon at the University of Buenos Aires, supported by Cardano, with a paper proposing a Cardano-based redesign of digital evidence custody. This is the short version of why the problem matters and what I learned while writing it.

Chain of custody is a protocol... on paper

Every legal process depends on answering one simple question: is this the same evidence that was collected, without alteration? Today the answer is a record of forms, signatures and seals — a protocol implemented through paper and people. Every human handoff is a failure point, as invalidated custody procedures demonstrate.

Our proposal is not to “put evidence on the blockchain” — a common mistake, since sensitive evidence should not be public. The idea is to record the interactions with the evidence:

• Every access, transfer or examination produces a cryptographic signature anchored to Cardano.
• The content never leaves the judicial environment; only the hash and custody metadata are published.
• Timestamping no longer depends solely on an administrative record and becomes independently verifiable.

Translating procedural requirements into protocol rules

The hardest part of the paper was not the technology, but the translation. “Signature by an authorized official” sounds straightforward until the system must decide: authorized according to which registry? Who rotates the keys? What happens if a court loses them? Every procedural requirement hides system-design decisions, and every technical decision has procedural consequences.

That is why the paper includes guidelines for a draft bill: without regulatory reform, the best protocol in the world is only a demo. Technology and law have to move together — that is, literally, the thesis behind everything I build.

From paper to practice

The natural next step is a pilot with low-risk case files, where the on-chain record runs in parallel with the traditional process without replacing it. That is the right pattern for judicial modernization: first demonstrate equivalence, then propose substitution.

If you work on the digitization of justice, digital evidence or DLT governance, write to me — the paper and its guidelines are meant to be discussed.