On 1 September 2026, the Ankara Chief Public Prosecutor’s Office opened an investigation in coordination with the Turkish National Intelligence Organisation (MİT) and the Counter-Terrorism Branch of the Ankara Police Department and announced simultaneous operations against what it described as the current information-technology structure of FETÖ/PDY. Detention warrants were issued for 13 suspects identified, according to the statement, in the course of work directed at organisational activity said to have been conducted through the encrypted messaging application Signal. Ten persons were detained on 1 September 2026; efforts to locate the remaining three were said to be continuing.

The statement placed Signal at the centre of the public discussion. It did not, however, set out the concrete messages relied upon, the individual conduct attributed to each suspect, or — crucially — the precise method by which any Signal material had been obtained. Use of Signal is not itself unlawful in Turkey. The legal question is therefore not whether the application was used, but how any data were obtained, how far they were disclosed to the defence, and whether they were converted into an automatic presumption of guilt.

It is in that setting that the case law of the European Court of Human Rights on ByLock, and the pending EncroChat, SkyECC and ANOM applications become highly important.

ByLock: the Yalçınkaya judgment and two core violations

The leading decision on ByLock evidence is the Grand Chamber judgment of 26 September 2023 in Yüksel Yalçınkaya v. Türkiye (Application no. 15669/20). The Court held that treating the mere use of ByLock, automatically and standing alone, as proof of membership of a terrorist organisation violated the principle of nullum crimen, nulla poena sine lege (Article 7 ECHR). It further held that the failure to give the defence access to the raw data and the technical method, and the domestic courts’ inadequate scrutiny of the reliability of the evidence, violated the right to a fair trial (Article 6). The core of the judgment is that the use of an encrypted application cannot be converted into an automatic conviction without an individualised assessment of the material and mental elements of the offence. If the source of the evidence, its integrity and the technical method by which it was obtained are not open to judicial scrutiny, the guarantees of a fair trial are undermined.

EncroChat and SkyECC: no final judgment on the merits yet

There is not yet a final ECtHR judgment finding a violation on the merits in EncroChat or SkyECC cases. In A.L. and E.J. v. France (Application nos. 44715/20 and 47930/21), two persons prosecuted in the United Kingdom on the basis of EncroChat data complained that France’s collection of the data and their transfer to the United Kingdom by European Investigation Order violated the right to respect for private life (Article 8), the right to a fair trial (Article 6) and the right to an effective remedy (Article 13). In its decision of 17 October 2024, the Court declared the applications inadmissible for failure to exhaust domestic remedies in France.

The Court has also communicated three further applications concerning EncroChat, SkyECC and ANOM to the respondent Governments.

In Silgir v. Germany (Application nos. 27618/21 and 22234/25), the applicant challenges a German conviction founded on EncroChat intercepts. The core complaints are that technical specifications and raw data were withheld from the defence and that lawyer–client communications were intercepted. The application relies on the right to respect for private life (Article 8), the right to liberty and security (Article 5) and, in particular, the right to a fair trial (Article 6).

Isha and Emmen v. Norway (Application nos. 7905/25 and 9417/25) concerns the use in Norwegian proceedings of EncroChat and SkyECC material obtained from the French authorities. The central issues are whether that material was decisive for conviction, whether its integrity and authenticity could be independently tested, and whether the defence had a genuine opportunity to challenge it.

Raal v. Estonia (Applications nos. 14711/25 and 14712/25) has likewise been communicated and remains pending. The ANOM proceedings raise structurally similar Article 6 questions. Unlike EncroChat and SkyECC, ANOM is said to have been conceived and operated in cooperation with law enforcement, which adds issues of investigative provocation, operational control and disclosure duties. The underlying fair-trial questions — effective challenge of the evidence, independent verification of authenticity, and equality of arms — substantially overlap with the SkyECC and EncroChat litigation.

Could the Signal fall into the same pattern?

The Signal situation will differ from EncroChat, SkyECC and ByLock. From the Ankara Chief Public Prosecutor’s Office statement, it appears highly likely that the suspects provided their phone passwords and that the messages in their accounts were accessed through the devices themselves. If so, the issue is not mass covert interception or the remote compromise of the application, but access to a seized telephone and the use of messages stored on the device. Accordingly, the central problem identified in the Yalçınkaya and EncroChat line of cases — the withholding of raw data and technical methods from the defence, and the conversion of the evidence into an automatic presumption of guilt — may not arise in the same way. That does not mean legal scrutiny disappears.

On the contrary, the following issues will still have to be examined with care:

• Was the password given voluntarily, or under pressure?

• Was the privilege against self-incrimination respected?

• Was the search and seizure lawful?

• Can the integrity, source and chain of transfer of the messages from the device be tested?

Conclusion

Encrypted messaging data is not, by itself, a presumption of guilt. The Court made that clear in the ByLock context and is now asking similar questions in EncroChat, SkyECC and ANOM cases. In the Signal context, the centre of gravity of the legal debate is likely to shift away from mass remote interception and towards seizure, consent, the privilege against self-incrimination, and the verifiability of the source and integrity of the messages. The decisive issue is not the name of the application, but how the evidence was obtained, whether it can be tested in court, and whether the guarantees of a fair trial were observed.

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How We Can Help | Turkut Legal

Turkut Legal advises on criminal and human rights cases involving encrypted messaging evidence — including Signal, ByLock, EncroChat and SkyECC — and prepares expert opinions for European courts on fair-trial standards, disclosure of raw data and technical methods, search and seizure, consent to device access, and the privilege against self-incrimination.

Our founder Dr Emre Turkut co-drafted an expert report on ByLock and the European Court of Human Rights, published by Statewatch, and has acted as an expert in legal proceedings concerning digital evidence.

If a case turns on whether messages obtained from a seized phone may lawfully support a conviction, whether the defence was given a real opportunity to test the integrity and source of the data, or whether the evidence has been treated as an automatic presumption of guilt, contact us so the legal risk can be documented with the necessary precision.