Facebook may not disclose documents about encrypting audio calls in the Messenger app, a US court ruled Tuesday, reports Reuters news agency.
The social network had to appear in court because two civil rights organisations want to clarify to what extent the audio conversations can be viewed during a police investigation. The Washington Post also wants the documents to be made public.
The chat app uses a form of encryption where only the two callers can view the data. The same type of security was more likely to lead to criticism by American police services, because they could not read messages from, for example, the iMessage messaging service.
According to the judge, documents about encryption in Messenger contain details about how police are trying to monitor calls. If the documents were made public, criminals would gain insight into how the police work.
Both the US Department of Justice and Facebook have spoken in the case, but their arguments have been kept secret because of the sensitive content. The parties involved may not speak about the matter with the media.
According to the judge, Facebook pleaded for the documents to be made clear, while the ministry was against it.