ECtHR Demirhan and Others v. Türkiye: convictions based on ByLock use alone violate Articles 7 and 6 § 1

In its Chamber judgment of 22 July 2025 the European Court of Human Rights found violations of Article 7 (no punishment without law) and Article 6 § 1 (fair trial) in respect of 239 applicants convicted in Türkiye of membership of an armed terrorist organisation. Following the Grand Chamber in Yüksel Yalçınkaya v. Türkiye, the Court held that the domestic courts' categorical approach, under which use of the encrypted messaging application ByLock could on its own establish all elements of the offence, was incompatible with the Convention and unduly restricted the rights of the defence. Reopening of the domestic proceedings would in principle be the most appropriate redress. The judgment confirms that data from an encrypted messaging service cannot serve as automatic proof of guilt. The attached document is the Court's press release; the full judgment is available in English on HUDOC.