I am thinking of creating a small chatting server. I want it to be as secure as possible so I found it to be very helpful if some expert could guide me a little bit.

Has there been any research on or perhaps a completely built prototype of a chatting server that doesn't know who chats with whom? That means, even if someone was to alter the code of the server, he wouldn't be able to learn the recipients of the messages.

I would like my server not to know who the recepient of the message I sent is. I figured something could be done with FHE cryptosystems, but for a simpler version which doesn't use any FHE, it should be possible to build something that can hide the recipients until the recipient receives the message. The simplest way to achieve what I want is to make every message broadcast. But, it is trivial and impractical so I am looking for something better. Broadcasting notifications, but sending the message to only one person seems to make some achievements. Using FHE cryptosystems should exclude all broadcastings and resolve my problem, but FHE systems are extremely slow.

Any guidance and hint is very welcome.

1 Answer 1


See Ricochet for an interesting project that allows users to chat privately, securely, and anonymously by routing connections over TOR.


  • Thank you for sharing this nice project! I liked reading about it. However, I am specifically looking for a server type of thing, so I won't mark this as an answer, I'm sorry.
    – donaastor
    Nov 26, 2021 at 1:35
  • @donaastor, In that case, any chat server, where the clients connect to the chat server through TOR, would fit the bill.
    – mti2935
    Nov 26, 2021 at 13:09

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