Switzerland: Zurich High Court Excludes Foreign-Obtained SkyECC Data for Breach of Territoriality and Lack of Sufficient Suspicion (Decision of 15 August 2025)

High Court of the Canton of Zurich

The Landmark Ruling on SkyECC Data Admissibility

As the Swiss representative within this network, I report on a recent interlocutory ruling of the High Court of the Canton of Zurich. Upon the defence’s request, the court examined the admissibility of SkyECC data obtained through investigative measures carried out in France. The court declared the evidence inadmissible and followed the defence’s reasoning in all essential respects.

Breach of Swiss Territoriality: The Core Violation

A key element is the territoriality principle. French authorities triggered a network manipulation that caused a SkyECC device located in Switzerland to transmit its cryptographic key to a server under French control. No authorisation had been sought from Switzerland, rendering the action an unlawful foreign coercive measure on Swiss territory. On this basis, the court held that the violation leads to an absolute exclusion of the evidence. It rejected any balancing approach based on the seriousness of the offence.

Absence of Individualised Suspicion Under Swiss Law

The court also found that at the time of the French measures no factual suspicion existed against the defendant, nor would Swiss law have permitted any form of surveillance. Blanket measures affecting all SkyECC users are incompatible with the requirement of individualised suspicion.

The ruling addresses further uncertainties surrounding the French authorisation orders, which various courts have interpreted as targeting platform operators, all users, SkyECC Global, or unknown persons. In none of these scenarios would the threshold of suspicion required under Swiss law have been met. In proceedings against unknown persons, any findings relating to third parties would merely constitute incidental discoveries. Some of the alleged conduct would not even amount to an offence justifying covert surveillance under Swiss law.

Future Implications for Digital Evidence and Defence

The court also considered the right of the defendant to access raw data. While leaving the issue open, it noted that the material provided does not constitute raw data in the sense defined by the European Court of Human Rights.

Following the ruling, Switzerland saw a wave of litigation-driven public relations aimed at influencing future decision-makers and shaping public perception by suggesting a threat to national security. In this climate, the work of defence lawyers acting across borders is more essential than ever.

The full reasoned judgment can be accessed here:

SkyECC_Switzerland.pdf

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