Designing the Chain of Custody Process for Blockchain-Based Digital Evidences.

The design of a chain-of-custody management system must be based on an architecture that guarantees non-manipulation in court, from the very beginning of the evidence is acquired to putting it on judge hands. Knowing, without doubt, who, when, how and why the involved actors were able to access it. This is a necessary condition, although not sufficient, for the court to decide on the admissibility of real the evidence. This way, the Blockchain technology is an optimal solution for issues where integrity must be guaranteed among untrustworthy parties. However, it is necessary to tackle a possible solution in a holistic way, by considering technologies, actors and industry involved during the process. Therefore, three basic architectural designs with different challenges are proposed in this work. In addition to this, we discuss about the need to promote a nationwide smart contract standardization for the chain-of-custody process. It must be open-source and compatible with current top languages used in the Blockchain landscape. These contracts must be deployed in consortium environments, where reliable independent third parties validate the transactions without knowing their specific content. This is possible thanks to the Zero Knowledge Proof protocols.