Facebook Messenger began testing end-to-end encryption on the Signal protocol

Facebook Messenger has begun the introduction of secret chats - end-to-end system encryption of communications between users. Unlike Telegram, which uses its own non-standard MProto protocol, Facebook chose a well-known and proven solution - a modern and open Signal Protocol , developed by Open Whisper Systems.

This protocol is used in the Signal reference messenger, as well as in WhatsApp, Google Allo messengers, and now in Facebook Messenger.

Apparently, the market is gradually forming an open standard for strong encryption for IM communications, which is supported by many popular programs (except Telegram).
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Facebook has published a document describing how it is used in the messenger encryption.


As stated in the datasheet, Facebook has applied the free Signal libraries from Open Whisper Systems.

In turn, the developers at Open Whisper Systems have confirmed that the integration of the libraries is correct.

It should be noted that in Facebook so far end-to-end encryption is not enabled by default for all communications, as is done in WhatsApp or Signal. Here the user must manually start a “secret chat”, as in a Telegram. A very small percentage of users refuse the default settings, so there is no talk of fully encrypting all conversations. But this is a step in the right direction. With an estimated 900 million users of Facebook Messenger, this is a really big step.

Let's hope that end-to-end encryption will become the standard way of communication and will be enabled by default in all instant messengers. In this case, the server operator does not own the keys to decrypt user messages and is not able to fulfill the requirements of law enforcement agencies to decrypt traffic. In Russia, such requirements for operators are going to be put forward in the near future, but in Brazil, for example, Facebook’s top manager was taken to the police station for questioning , and the work of the WhatsApp service across the country was blocked twice (for 12 and 48 hours) because that whatsapp (owned by facebook) turned out to provide the authorities with information about the criminals who used whatsapp to communicate.

Facebook security director Alex Stamos (Alex Stamos) writes that encryption is not enabled by default for several reasons.

First, Facebook Messenger supports work from several devices, and if you activate E2E, this support will be lost (keys from one device cannot be used on another). It should be noted that, in general, the Signal protocol supports work on several devices, so the problem here is rather in a specific technical implementation.

Secondly, some popular functions do not work in secret chats, such as searching in the message history, voice and video, the same device switching mentioned above.

Thirdly, hundreds of millions of people use Messenger through a browser , and in this case there is supposedly no way to securely store keys and encrypt messages, if not redirect them via a mobile device.