Sponsoring Group Chat Encryption in Siskin

Posted by Matthew Wild on November 30 2020

For some time XMPP has been in need of a good solution for Apple’s mobile operating system, iOS. In 2020 we now have a number of active projects. Work on the long-standing iOS (and now also MacOS) client Monal IM has really picked up in recent months, in no small part thanks to the efforts of tmolitor, who has been contributing a lot of modernization to both the UI and the internals.

Tigase also released an open-source iOS client, Siskin IM that has been making steady progress recently.

Monal IM

Monal IM

Siskin IM

Siskin IM

It’s exciting to see so much activity happening around XMPP on iOS now, and both projects are adding more modern XMPP features with every release. Snikket does not currently have an official iOS client, so we’ve obviously been keeping a close eye on these advancements.

A major interoperability problem between the current version of Siskin and other modern XMPP clients is that it does not support end-to-end encryption (OMEMO) in group chats. This means that users of Siskin cannot participate in private group chats started by Conversations or the Snikket client on Android, because they are end-to-end encrypted by default.

OMEMO is a form of “end-to-end encryption”, which means that it hides message contents from the servers and operators of each chat participant. Siskin already supports OMEMO for one-to-one conversations, but not group conversations.

One of the goals of Snikket’s CIC is supporting and advancing the XMPP ecosystem. With that in mind, we’ve been working in recent months to obtain funding to close this gap in Siskin. Today we are pleased to announce that thanks to a private donor, the project can now move forward. The Tigase team will commence work on OMEMO in MUC in the coming weeks!

This is really exciting news, and will bring the XMPP experience for iOS users an important step closer to that of other platforms. There will be more announcements in the future, stay tuned!

If you want to help us with our goals and other projects like this, consider a donation, contribute in some other way, or simply help spread the word! The future of XMPP is coming :)