EncroChat and SkyECC: Why European Courts are Questioning the Reliability of Digital Evidence

Joint Defense Team
2 days ago
3 min read

In recent weeks, the legal landscape regarding the reliability of digital evidence has faced intense scrutiny. As landmark rulings emerge across Europe, the "blind trust" in encrypted data is being replaced by fundamental principles of a fair trial.

The Digital Evidence Debate: Beyond State Secrecy

Since 2020, the technical aspects of EncroChat and SkyECC cases have been at the heart of legal discussions. For years, these debates often led to dead ends due to claimed state secrecy and legal hurdles, such as the (arguably wrongful) application of the principle of mutual trust in cross-border investigations.

Consequently, digital expert witnesses were frequently barred from conducting proper research, while legal practitioners often struggled to recognise the fundamental threats this posed to the correct finding of facts.

Landmark Rulings in Spain and Italy

Significant legal and factual developments are now emerging. In both Spain and Italy, courts have recently concluded that decrypted communications cannot be used as evidence because the defence was denied the opportunity to verify the reliability, correctness, and completeness of the data.

Spain: The SkyECC Ruling and the Yalçınkaya Precedent

In the Spanish case involving SkyECC data, the court in Valencia excluded the evidence, referencing the landmark decision of the Grand Chamber of the European Court of Human Rights (ECtHR) in Yalçınkaya v. Turkey. The court argued:

Presumption of Innocence: The court argued that without effective contradiction of the data, the presumption of innocence must prevail.
Reasonable Doubt: Suspects should benefit from the reasonable doubt arising from untested digital evidence.
Data Vulnerability: The ECtHR highlighted that digital evidence is inherently prone to destruction, damage, alteration, or manipulation.

As the ECtHR stated in the Yalçınkaya case, digital evidence "raises distinct reliability issues as it is inherently more prone to destruction, damage, alteration or manipulation."

This decision reinforces that the reliability of digital evidence cannot simply be assumed; it must be treated with the utmost care, as outlined in the Council of Europe’s Electronic Evidence Guide.

You can find the full decision here:

The Italian Decision (EncroChat)

In a parallel development in Italy concerning EncroChat data, the presiding judge was not convinced "beyond reasonable doubt." The judge explicitly noted that because the appointed expert could not test the reliability of the data, the evidentiary value was insufficient.

This decision directly aligns with the Court of Justice of the European Union (CJEU) ruling of 30 April 2024 (the ‘EncroChat case’). The CJEU made it clear: The responsibility to check the reliability of evidence lies solely with the trial judge.

If the defence cannot scrutinise the data, the judge cannot be satisfied of its integrity.

Practical Failures: The Belgian Experience

These concerns are not merely theoretical. In a recent case before the Court of Appeal in Antwerp, Joint Defense Team members Justus Reisinger, Guillaume Martine, and Louis R. De Groote defended an accused where the prosecution presented different datasets that were supposed to be "identical".

An investigation by a UK-based digital expert revealed:

Significant Discrepancies: The datasets were not identical, despite prosecution claims that new decryptions were responsible.
Data Unreliability: Multiple specific errors led the expert to rule the dataset itself as "unreliable".
The Necessity of Raw Data: The expert concluded that the only way to provide an adequate review of reliability is through access to the raw data and the complete chain of evidence.

Beyond the "Digital Truth"

The idea that "computers don't make mistakes" or that "readable text equals correct decryption" is a dangerous oversimplification. Digital forensics and common sense dictate that the reality is far more complex.

These cases underscore the vital importance of specialized knowledge and experience in the defence. All members of the Joint Defense Team (JDT) are highly experienced in handling digital evidence and understand how to properly examine it to protect the rights of the accused.