From admissibility to contestability: Structural opacity, encrypted-platform evidence, and the limits of adversarial review
From admissibility to contestability: Structural opacity, encrypted-platform evidence, and the limits of adversarial review

Summary/Abstract: Digital evidence from encrypted platforms such as EncroChat and Sky ECC is increasingly treated as formally admissible across multiple jurisdictions, yet core questions of provenance, integrity, and attribution remain structurally resistant to adversarial testing. Existing scholarship has mapped the doctrinal and cooperation routes through which such datasets enter domestic proceedings, but has not sufficiently operationalised the conditions under which they remain genuinely contestable once admitted. This paper addresses that gap through a doctrinal analysis of selected EU, ECtHR, and domestic case law, combined with a normative analysis of Serbian criminal procedure and recent regional scholarship on digital evidence. It argues that structural opacity is sustained by cross-border procedural architecture, confidentiality constraints, and restrained legality review under mutual recognition, and that formal admissibility cannot by itself secure fair evidential use where the defence cannot test method-relevant premises. The paper makes three original contributions. First, it proposes a minimal contestability test structured around provenance, integrity, and attribution, together with a staged verification package designed to function under persistent secrecy. Second, it develops a tiered remedial model linking failed contestability to calibrated procedural consequences, from reduced weight and mandatory corroboration to exclusion where the material is sole or decisive. Third, it maps contestability onto the Serbian Criminal Procedure Code and shows how existing procedural levers can operationalise the framework without legislative change. The paper further argues that the EU AI Act is relevant only as an external traceability benchmark for algorithmically processed investigative outputs, but not as a direct source of evidentiary law.

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