ActivityPub Gateway and Pubsub e2ee

goffi 3 years ago jabber-xmpp-en SàT Libervia project libre ActivityPub e2ee


it's my pleasure to announce that an ActivityPub <=> XMPP gateway doubled with Pubsub end-to-end encryption project has been selected for a grant by NLNet/NGI0 Discovery Fund (with financial support from European Commission's Next Generation Internet programme):

This big project is split in 27 steps, and will take most of my time dedicated to the Libervia project (formerly "Salut à Toi", the project has been renamed, I'll explain that in a upcoming progress note).

The XMPP <=> ActivityPub gateway will join two major open and decentralised protocols. In practice it will be a XMPP server component (usable with any server), and implement the ActivityPub server to server protocol (or "Federation Protocol"). On XMPP side, it will be mostly a Pubsub service (with some extra, like private messages converted to XMPP message stanza).

XMPP blogging (XEP-0277: Microblogging over XMPP) will be used, and thus any client supporting it will have access to ActivityPub publications (Libervia and Movim for instance).

For features present in ActivityPub and not yet in XMPP, it is planned to propose protoXEPs (i.e. proposition of XMPP extensions), to implement them. Events will also be part of the project, with a compatibility between Mobilizon and Libervia expected, and a protoXEP to have this standardised on XMPP side.

This is quite exiting, as it will extend both networks, and boost projects integrating blogging and XMPP chat.

The second part of the project is about end-to-end encryption. XMPP has enjoyed major improvements on end-to-end encryption following the work done on OMEMO, notably initiated with Conversations, and on OX, modern OpenPGP integration. This is great, but has been so far mainly focusing on instant messaging. The goal will be here to add end-to-end encryption to XMPP Pubsub, which includes protoXEPs and implementation in Libervia. In other terms, at the end of this project, it will be possible to use e2ee with all Pubsub based features (like blogs, forums, lists, or events that you can do on Libervia), this is huge! Signing will be part of the project too, meaning that it will be possible to authenticate something like a blog post in a standardised way.

Beside the standards which will benefit to the whole XMPP community, all of this will be implemented in Libervia, this include updating current implementation to the state of the art (i.e. updating current OMEMO implementation and implementing OX).

Last part of the project will be the implementation of e2ee in the web frontend. Due to Libervia specific architecture, OMEMO is not currently usable from the browser (the implementation is done on the backend). To make this possible, the Python OMEMO library which is currently used will be ported to WebAssembly and Brython, allowing to do encryption and decryption directly within the browser.

As you can see this is massive. I'll do most of this but I won't be alone (notably the author of Python OMEMO will do the wasm/Brython port as part of the project). The project should last circa one year, with the ActivityPub <=> XMPP gateway being the first part worked on.

I would like to thanks again NLNet and EU's NGI for allowing this, and my employer (Sourcefabric, which notably develops Superdesk) for letting me adapt my working schedule.

I've adapted the tasks to Libervia's (XMPP powered) bug tracker, so you can see step details and follow progress there:

Also I'll continue to publish progress notes so stay tuned to this blog (that should be available also on ActivityPub later this year ;) ). The website has been updated, with new Flatpak and Docker installations, check

If you have questions or comments, feel free to join Libervia's XMPP room at or to contact me for instance via ActivityPub (

See you soon.

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