NÚKIB published an analysis of communication applications, where Signal and Threema performed better

Publication of the National Office for Cyber ​​Security and Information Analysis of communication applications with end-to-end encryption [PDF]. I checked Threema, Signal, Telegram, WhatsApp, Facebook Messenger, Google Messages, and Apple iMessage features. The analysis was created primarily for organizations covered by the Cyber ​​Security Act, but can serve as a guide for the general public.

The document addresses, for example, national jurisdiction, encryption support for groups and bilateral communications, support for the Czech language, retrieval of personal data, automatic deletion of old messages, and the multi-platform system. The best rating was given to Signal, which was previously issued by NÚKIB Recommendations for safe use. The app is only criticized in practice because it asks the user to enter a phone number, and therefore cannot be used completely anonymously.

Threema is also rated very well, which, according to the authors of the analysis, cares about Maximum security and privacy at the expense of reduced user comfort. Threema provides complete anonymity, strong end-to-end encryption, and allows you to set unique passwords to access individual conversations. The advantage is also the Swiss jurisdiction and transparent financing thanks to the payment of the application.