Wednesday 25 October 2023

Systemic Problems Unveiled: The Yalcinkaya Case and the Demise of the Bylock Digital Evidence

By Dr. iur. Yasir Gökce

The Turkish Government has declared the Gülen Movement a terrorist organization and blamed the Movement for orchestrating the 2016 coup attempt. To identify the members of this organization, the Government has controversially decided that any individual who downloaded and/or used the ‘ByLock’ encrypted messaging application was part of the Gülen Movement and thus can be charged with terrorism membership. Thousands of affected individuals have found the measures to be erroneous and unlawful.

On 26 September 2023, the Grand Chamber of the European Court of Human Rights (Court or ECtHR) in Yalcinkaya v Türkiye examined the human rights implications of the use of the ByLock app. In this landmark judgment, the Court found a violation of Articles 6, 7 and 11 of the Convention. Referring to thousands of applications on its docket involving similar complaints, the ECtHR stressed that the problems which had led to findings of violations were systemic in nature and called on Turkey to take general measures as appropriate to address those systemic problems.

The case was lodged by the applicant, Mr. Yalcinkaya, who had been dismissed from his public service as a teacher with the state of emergency decree no 672 after the botched 2016 coup attempt and convicted of terrorism membership due to his alleged link with the Gülen Movement, an organization designated as terrorist by the Turkish Government. Such link was established in Mr. Yalcinkaya’s domestic penal proceedings from his alleged use of an electronic communication app, namely ByLock, his membership of a lawfully established trade union (Aktif Eğitim-Sen) and an association (Kayseri Voluntary Educators Association) and his use of a bank account.

In this contribution, I examine the analysis carried out by the European Court of Human Rights on the approach of the Turkish judiciary vis-à-vis the digital evidence under Articles 6, 7, 8, and 11 of the Convention, uncovering both what the Court well-appreciated and missed. The concluding paragraph elucidates why this judgment is of utmost importance for the human rights protection mechanism in Turkey.

The Court’s Findings under Article 7 of the Convention

Under Article 7 of the Convention, the ECtHR examines the ‘exclusive use’ argument of the Turkish government and its practical implications for the applicant. The government purports that the Bylock app was exclusively designed and used by the Gülen Movement for its secret communication needs, despite the fact that the app had been downloaded approx. 1 million times from open sources. Such narrative of the ‘exclusive use within a closed domain’ was dictated by the government on judicial authorities in the form of a technical expert report produced by the Turkish intel agency. Eventually, this narrative led the judicial authorities to summarily convict any individuals, including the applicant, whose digital footprints had been somehow discovered in Bylock servers, of terrorism membership, irrespective of the content of the messages exchanged or the identity of the persons with whom the exchanges were made (§ 258).

Against this backdrop, the Court first elucidates that, under the Turkish law and jurisprudence around terrorism membership, the elements of the crime are fulfilled “where the accused’s organic link with the armed organization is established, based on the continuity, diversity, and intensity of his or her activities, and where it is demonstrated that he or she acted knowingly and willingly within the organization’s hierarchical structure” (§ 184). The Court then reveals the automaticity and certainty with which the domestic courts equate the mere download and/or use of the Bylock app with the membership of an armed terrorist organization. In other words, an individual who allegedly used the app has met, as the Court reveals, the continuity, diversity, and intensity criteria, as well as the criterion of acting knowingly and willingly, prescribed in Turkish law (§ 264). Eventually, the Court concludes that the reliance on the mere use of the Bylock app without establishing the presence of the constituent material and mental elements of the offense in an individualized manner corresponds to an unforeseeable application of the law lying outside of what the law proscribes. Therefore, it holds that Turkey has violated the principles of legality and foreseeability as well as individual criminal responsibility, which are enshrined in Article 7 of the Convention (§ 267).

It is praiseworthy that the ECtHR examined the case within the ambit of Article 7 and to the extent that it concerns not only the applicant but all victims prosecuted and arrested owing to the ‘exclusive use’ narrative of the Turkish government. However, I find it unfortunate that the Court overlooked the fact that the Turkish judiciary had applied the material and mental elements of the offense retrospectively. In other words, at the time of the acts attributed to the applicant, namely the Bylock usage, the Gülen Movement was not proscribed as a terrorist organization and, on the contrary, enjoyed a wide and respectable presence in all sectors of Turkish society. Furthermore, it would have been, at the very least, an eye-opener for the Turkish government if the Court had scrutinized whether this secret communication app was used during and/or for the purpose of staging the 15 July coup attempt, which the government alleges, has been orchestrated by the Gülen Movement and due to which, by and large, the latter was declared as a terrorist organization. Yet another approach of the Court, which I also find unfortunate, is that it addressed the issue of using a secret communication app not primarily as a mere enjoyment of the freedom of expression and right to respect for private life but as potential conduct that might form the constituent elements of the offense of terrorism. On the contrary, such a rights-oriented approach was the one adopted in various Bylock-related opinions of the United Nations Working Group on Arbitrary Detention (UNWGAD).

The Court’s Findings under Article 6 of the Convention

The Court’s finding on the violation of the right to fair trial pertains to the applicant’s assertions concerning the integrity and reliability of the Bylock raw data as well as the legality of its collection and analysis by the Turkish intel agency, a.k.a. the MIT. As also acknowledged by the government, by the time a domestic court issued a seize order for the Bylock servers, the MIT had long collected the Bylock raw data and analyzed it not only for intelligence purposes but also to initiate criminal proceedings (§ 334). It remains unknown on what legal grounds the MIT collected the data and under compliance with which legal and digital forensic principles it examined those data and identified the users as potential terrorism suspects. For instance, a number of independent digital forensic experts (herehere, and here), which were repeatedly referred to by the applicant, uncover numerous traces of concrete manipulation of the data collected by the MIT as well as a biased analysis methodic such as to vindicate some pre-determined outcomes. The mere fact that the MIT has reduced the number of people who downloaded ByLock from over 1 million to 215,000, then to 102,000, and then to 91,000 raises serious concerns regarding the accuracy and reliability of the ByLock data.

Having been cautious in refraining from acting as an appellate court by analyzing the admissibility of the Bylock findings, the ECtHR scrutinizes the applicant's concerns summarized above under the principles of equality of arms and adversarial proceedings. In this vein, the Court examines whether the applicant was granted procedural safeguards that would enable him to raise those concerns in the criminal proceedings (§ 316, §317). The Court first determines whether the applicant’s concerns on the integrity, reliability, and legality of the Bylock findings lay at the core of the case and were essential for concluding it (§ 332, § 345). After establishing the essentiality and vitality of those concerns, the Court examines how the domestic courts reacted to them. The Court notes that the applicant’s persistent requests that the Bylock raw data be made available and accessible to him or be sent for an independent examination simply went unanswered. Nor the aforementioned inconsistencies and irregularities raised by the applicant were addressed by the domestic courts, as noted by the ECtHR. The Court concludes eventually that the applicant was deprived of sufficient safeguards to equip him with a genuine opportunity to challenge the evidence against him and conduct his defense in an effective manner and on an equal footing with the prosecution (§ 341). This conclusion led the Court to find the violation of the right to a fair trial enshrined in Article 6 of the Convention.    

Having observed that the individual internet traffic information and telecommunication records (a.k.a. CGNAT and HTS data) are in line with the data obtained by the MIT from the Bylock servers, the ECtHR indicated that it does not have sufficient elements to impugn the integrity and accuracy of the Bylock data (§ 323). It is unfortunate that, in this observation, the Court overlooked numerous traces of manipulation of the Bylock raw data documented in technical reports of independent digital forensic experts (herehere, and here), which the applicant relied upon throughout this case. These reports cast serious doubts on the integrity and accuracy of the Bylock data. Furthermore, the Court failed to appreciate the seriousness of the fact that the individual internet traffic information and telecommunication records had been obtained outside the statutory time limit. After the expiration of the retention period, those records were kept under the custody of the information and communication technologies authority and the MIT with no legal basis at all, as had been the case for the initial period of the Bylock raw data. In other words, those records are also fraught with illegality and lack of chain of custody and highly prone to manipulation. And yet the Court observed that the accuracy of the Bylock raw data could be substantiated with some records whose accuracy is itself under suspicion. Last but not least, the Court refrained from pronouncing a violation from the standpoint of the right to privacy enshrined in Article 8 of the Convention. Although a great volume of private communication data of the applicant was seized and processed unlawfully, unforeseeably, and irresponsibly, the Court considered his arguments to this effect peripheral and not having situated at the heart of his complaints, a reasoning which seems unsatisfactory (§ 371, §372).


Immediately after the publication of the judgment, the Turkish minister of justice displayed his resentment with the finding of violations, criticizing the Court for analyzing the evidentiary value of the Bylock findings and thereby acting as a “court of appeal” in contrary to its well-established precedence. This concern was also conveyed by the government in its submission in the form of a warning for the Court to refrain from acting “as a court of ‘fourth instance’ by questioning the conclusions reached by domestic courts or to substitute its own views for their findings” (§ 289). In the face of this remark, the Court adopts throughout the decision a cautious approach, whereby it keeps reminding that it is not competent to review the weight attached to evidence or to ascertain how digital evidence is to be collected or admitted in criminal proceedings (e.g., §243, §255, §302, §316, §412). On the other hand, the Court also reminds that it would remove such restrain when the domestic authorities reach conclusions or pronounce judgments in an arbitrary or manifestly unreasonable manner and to the extent that those conclusions and judgments infringe rights and freedoms protected by the Convention (§ 302, §304).

Overall, this landmark judgment of the Grand Chamber stands out, by and large, with its well-examination, meticulous scrutiny, and spot-on conclusions, and sets a powerful precedent for pending and prospective cases of similar nature. The judgment delivered a resounding message regarding the protection of fundamental human rights, as it uncovered severe violations of key provisions of the Convention. In parallel with the finding of the UNWGAD that the deprivation of liberty in Turkey is systematic, the Court describes the problems that had led to findings of violations as being systemic in nature. It takes attention to approximately 8,500 applications on the Court’s docket involving similar complaints under Articles 7 and/or 6 of the Convention and to tens of thousands of potential applications to come, as hinted at by around 100,000 ByLock users according to official figures from Turkey. Eventually, referring to Article 46 of the Convention, the Court calls on Turkey to take general measures as appropriate to address the systemic problems that led up to the violations stemming from the Turkish judiciary’s approach to Bylock evidence (for a deeper analysis on how the judgment should be adopted by the Turkish judiciary, see here). It remains to be seen whether Turkey will abide by the judgment, although President Erdogan's remarks on the judgment at the opening ceremony of the new legislative appears not reassuring. Against this backdrop, it is up to the victims to be proactive and vigilant and have the judgment included in their respective case dossiers or lodge applications for retrial on the basis of severe violations found in the judgment.