What is secure - as in confidentiality of message contents - instant messaging software with at least following features:

  • No need to setup (and maintain) my own server
  • Support for Windows, OS X and Linux
  • End-to-end encryption to prevent listening message on the server
  • One-to-one and group chats

3 Answers 3


You may use any XMPP client that supports OpenPGP or OTR. So each person could use a client of their choice, no need for all to use the same.

But if the same client should be used cross-platform, have a look at Jitsi (License: LGPL), which uses Java. It supports OTR. See this (old) video: Your first OTR text chat with Jitsi.

(XMPP works, like email, not with a specific provider only. So you can make your choice which provider to use, and again, each person could use a different one. For example @jabber.org, @dukgo.com, @gmx.com, …)

  • I think it's okay to use different software on different platforms, as long as those are compatible. But Jitsi seems to fit rather well.
    – Olli
    Commented Feb 5, 2014 at 1:54
  • 2
    Related question: Which XMPP clients support OpenPGP (XEP-0027)?
    – unor
    Commented Feb 6, 2014 at 11:13
  • +1 XMPP and OTR should cover the need really well, I do use them myself everyday. Commented Feb 9, 2014 at 17:47
  • 2
    I'm throwing in pidgin.im . Available for all OS and prepackaged for most Distributions.
    – cete3
    Commented Feb 20, 2014 at 17:24
  • 1
    OTR is great for one-on-one conversations, but it doesn't support group chat, which was one of the requirements set forward by the OP. There has been considerable talk about a multi-party OTR (mpOTR for short) in the past years, but as far as I know so far they didn't pan out, yet.
    – A.P.
    Commented Mar 19, 2016 at 1:27

You can try Tox, a new encrypted IM client. It's in alpha stage, but the chat feature seems to work quite well.

It has all the features you want:

  • One on one messaging and group chats.

  • It encrypts messages.

  • Supports Mac OSX, Windows, and Linux.

  • No setup needed.

Venom UI

As mentioned earlier, the software is still in an alpha state, but I think it shows a lot of promise.

  • Is it still in alpha state? Commented Nov 27, 2015 at 0:53
  • No, it is no longer in alpha state.
    – mic
    Commented Aug 20, 2019 at 20:18

You could use Cryptocat, a browser extension for encrypted chatting (similar to IRC, but more secure ;)

Cryptocat supports all major browsers including:

  • Chrom(e)(ium)

  • Firefox

  • Safari

  • Opera

  • OSX via the Apple App store.

Cryptocat UI

  • 1
    One of the requirements is “no need to setup (and maintain) my own server”. Are there public Cryptocat servers? Commented Feb 5, 2014 at 1:59
  • @Gilles Yes, there are public Cryptocat servers… accessible via their browser extensions and apps. Here's their network monitor (third-party cryptocat networks not included). Btw.: Cryptocat's network is located at "Bahnhof" (Swedish webhost, known for having hosted WikiLeaks and The Pirate Bay).
    – e-sushi
    Commented Feb 5, 2014 at 4:46
  • 1
    Quick update: Cryptocat has been unavailable since February 2015, due to it's author's lack of time. In his message on crypto.cat he mentions a full rewrite of the Cryptocat software, but it is unclear if/when this will be available.
    – A.P.
    Commented Mar 19, 2016 at 1:33

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