Amnesty International has put together a ranking of the 11 companies that run the most popular instant messaging apps, based on how they protect users’ privacy and freedom of expression. Facebook’s apps – WhatsApp and Messenger –, with 2 billion users, top the list for their use of encryption, though it also delves into the differences between the two apps.

While WhatsApp is “the only app that expressly notifies users when end-to-end encryption is not applied to a given chat”, Facebook Messenger does not employ end-to-end encryption by default, and does not warn users users that normal conversations use a weaker form of encryption. End-to-end encryption, a security system that means that only customers and not the company can see the texts, was introduced by default in WhatsApp at the beginning of the year, something that users were able to notice through messages. However, new problems have arisen since then: WhatsApp announced that will share user data with Facebook, a matter that is being investigated by the European Commission for going against competition rules.

Close in score to Facebook are Apple – with Facetime and iMessage – and Telegram. The latter was introduced with a strong position to promote privacy in communications, so AI is surprised that it does not use end-to-end encryption by default, and users are not prompted when using weaker encryption. Behind them are Google – with Hangouts, Allo, and Duo – or Line, very popular in Japan and Southeast Asia.

Among those who do not reach the pass is Microsoft with Skype, which is classified as a major target of government surveillance with weak encryption, and lastly, Snapchat, whose “self-destructing” messages give a “false sense of privacy ” to users.