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I figure this app deserves a wider audience.

OTR (Off-The-Record) is a popular protocol for end-to-end encryption, and has been implemented in a number of apps: Signal, WhatsApp, Facebook Messenger, and Google Allo all use OTR with the Axolotl Rachet algorithm.

However, OMEMO offers some improvements over OTR. It enables easy, multi-device, multi-party, offline-capable, forward-secure chat encryption over XMPP.

Using the OMEMO protocol would be interesting enough by itself, but Conversations' additional innovation is that it avoids using the Google Cloud Messaging service without significantly impacting battery life.

The default server is free to use for six months, afterwhich you need a subscription. Or you can simply host your own XMPP server.


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    Open Whisper Systems invented the OTR (Off-The-Record) protocol in 2014,

    This cannot be right. I have been using OTR much longer than that.

    See https://lists.cypherpunks.ca/pipermail/otr-users/2014-October/002515.html

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      Thanks for the correction, I got some wires crossed. Apparently OTR, the Signal protocol, and the Axolotl Ratchet algorithm are all different things.

      I found some discussion of the differences between Axolotl and plain OTR here. Apparently the Axolotl algorithm made it practical to use OTR on mobile devices, since the key exchange can happen asynchronously (among other features).

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      I use it and like it. But calling it the last word is a bit of a stretch. A peer-to-peer solution would be much better than relying on servers.

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        The trendy way to do that these days is to throw a blockchain algorithm at it, right? A conversation is kinda like a ledger. I’m sure it’ll be great.

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          I am not a blockchain expert, but doesn’t this mean that every client potentially has to download quite a lot of data?

          There have been some attempts to do P2P chat via the Bittorrent DHT (e.g. Bittorrent Bleep).

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            I was mostly being sarcastic because there seems to be a slice of developers out there that wants to use the blockchain for every problem. Voting? Blockchains! Supply chain management? Blockchains! (Okay, that’s actually probably a good use).

            I think with a few tweaks, you could make it work by taking advantage of something that a currency-oriented blockchain tries to stop: forks. A chat system doesn’t need a globally coherent log- you just need branches that are internally consistent.

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            I was thinking more like Matrix or GNUnet.

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          When I think of “the very last word” I think of an application which can bring several messaging services together. This was true for a short period of time with iChat, Adium, and especially Messages (which incorporates SMS as well).

          Until SMS goes away, the default messaging app, especially on iOS, will be the most popular and most necessary.

          The sad thing about XMPP is that services like Facebook have abandoned it in favor of proprietary networks and so XMPP isn’t as useful as a way to bring everyone together.

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            That is a sad thing about the world and about Facebook, not about XMPP.

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              Disagree. Wide adoption is a characteristic one can judge technologies against. It may have nothing to do with the protocol technically, I’ll give you that…

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                I’m pretty sure that the main problem with XMPP at Facebook was the fact that you could use a third-party client instead of a client built and owned by Facebook.

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            I could see this being super useful for orgs that want to self host their own IM.

            However Slack and Mattermost seem to be taking over the world these days, security be damned :)

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              Matrix and Riot seem to be gaining press. This is a good thing.

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                However Slack and Mattermost seem to be taking over the world these days, security be damned :)

                Not sure if I’m missing something in your comment, but Mattermost is open source and self hosted.

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                  Mattermost is free software, but it doesn’t federate. XMPP does. Matrix does.

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                  And on more whimsical fronts (such as gaming) Discord seems to be taking over as well…

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                  Wow, XMPP got a lot better in the past few years. Better server side history and push make it much better for an IRC alternative.