End to end message encryption, which algorithm/library to choose?

Question

Encryption

Hello.
In order to develop practice in node.js, I want to create something like a telegram, with a server and a browser client. Since I never immersed myself in cryptography and began to wool the network on this topic, I very quickly remembered the concept of "live and learn". After the algorithms used by Telegram, asynchronous and synchronous keys, Diffie, etc. I realized that to cover all this information would take twice as long as the original task. This begs the question, are there open source algorithms, libraries for creating secure, encrypted messaging?
Idea/requirements:
The server should not be able to read the messages, i.e. it will store messages for a while, but will not own the keys. Encryption must occur exclusively on the client, MIM standoff.
Of course, the question is more in the presence of choice. I will take the best possible and, unfortunately, I could not yet find the very one.
I would be grateful for the names of existing solutions that you can advise me.
Thanks a lot

Answer 1

There is a certain standard in the form of an open source Signal: https://www.signal.org/
They have everything in this regard open and painted.
Design docks: https://www.signal.org/docs/
Code: https://github.com/signalapp
There is also a link in the design docks to their ready-made JS library for working with their protocol:
https://github .com/signalapp/libsignal-protocol-ja...

Answer 2

VirgilSecurity has free SDKs for all platforms + ready-made chat examples with E2E encryption
For example, firebase https://medium.com/@geekyants/implement-virgil-sec...