Add post about E2EE using Emacs matrix-client.el

content/blog/2020-03-09-chatting-on-matrix-with-e2ee-from-emacs.rst

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+Chatting on Matrix/Riot with end to end encryption from within Emacs
+####################################################################
+
+:date: 2020-03-09T11:48Z
+:category: blog
+:tags: emacs,matrix
+:url: 2020/03/09/chatting-on-matrix-with-e2ee-from-emacs/
+:save_as: 2020/03/09/chatting-on-matrix-with-e2ee-from-emacs/index.html
+:status: published
+:author: Gergely Polonkai
+
+Iʼm a happy user and administrator of a `Matrix <https://matrix.org>`_ instance.  Itʼs a pretty
+lonely one (iʼm the sole user of it) but i faced a lot of pros and cons of it in the last few
+years.  In case you havenʼt heard about Matrix yet, itʼs a messaging framework which, for a few
+years now, supports end to end encryption (E2EE).  It also serves as the base of a federated chat
+service you might know as `Riot <https://riot.im>`_.
+
+Another thing iʼm also fond of is Emacs.  Itʼs a great little UI for pretty much everything i do,
+from note taking through managing email and calendar to software development.  It even has a
+Matrix client, `matrix-client.el <https://github.com/alphapapa/matrix-client.el>`_, written by
+well-known (in Emacs circles at least) `Ryan Rix <https://whatthefuck.computer/>`_ (rrix) and
+`alphapapa <https://github.com/alphapapa>`_.  I tried it several times, but at the end i always
+came back to the official Riot client because we use Emacs E2EE both at my company and in private
+with some friends, and unfortunately ``matrix-client.el`` doesnʼt support it.
+
+As this is the case with many other clients, like Fractal, some awesome folks of the Matrix
+community wrote `Pantalaimon <https://github.com/matrix-org/pantalaimon>`_ to solve this problem.
+It’s a Matrix proxy that can do E2EE for clients that donʼt support it natively.
+
+Pantalaimon
+===========
+
+Setting up Pantalaimon is really easy: you ``pip install`` it, write a 4 lines long config fire, and
+you are ready to go.  Just make sure you have a valid certificate if you use HTTPS; Pantalaimon
+wonʼt connect if not, and will communicate this problem poorly.
+
+.. code:: dosini
+
+   [example-matrix]
+   Homeserver = https://example.org/
+   ListenAddress = 127.0.0.1
+   ListenPort = 8765
+
+You simply start it with ``pantalaimon`` or, if you are a systemd fan user, you can use the
+`service file from their repository
+<https://github.com/matrix-org/pantalaimon/blob/master/contrib/pantalaimon.service>`_ with a
+slight change in the path.
+
+matrix-client.el
+================
+
+Coming up next, the Emacs Matrix client.
+
+The fastest route for me was to add ``quelpa`` and ``quelpa-use-package`` to my config, and
+install matrix-client.el using those.  The only tricky part is that iʼm lazy, so i have
+``use-package-always-ensure`` enabled which doesnʼt play nice with Quelpa installed packages that
+are not otherwise available on MELPA (or any other repository you might have enabled), hence the
+``:ensure nil`` clause.
+
+.. code:: common-lisp
+
+   ;; Don’t use it unless you are lazy enough to do extra work later
+   (customize-set-variable 'use-package-always-ensure t)
+
+   (use-package quelpa)
+
+   (use-package quelpa-use-package
+     :after quelpa)
+
+   (use-package matrix-client
+     :after quelpa-use-package
+     :ensure nil  ;; you only need this if you have `use-package-always-ensure' set to non-nil
+     :quelpa (matrix-client :fetcher github :repo "alphapapa/matrix-client.el"
+                            :files (:defaults "logo.png" "matrix-client-standalone.el.sh")))
+
+Run it!
+=======
+
+At this point you are ready to go.  In Emacs, run :kbd:`M-x matrix-client-frame` or use the
+standalone script ``$HOME/.emacs.d/elpa/matrix-client-VERSION/matrix-client-standalone.sh`` to run
+it in a separate process (might be a better choice if your server is lagging a lot).
+
+When ``matrix-client.el`` is asking for your credentials, you just enter them: your User ID (MXID,
+looks like ``@user:example.org``) and your password is as usual.  Your server should be the one
+you specified in your Pantalaimon config as the listening IP and port, so in my example it would
+be ``http://localhost:8009``.  If you donʼt need E2EE, then you can simply enter your homeserverʼs
+address here (and thus you donʼt need Pantalaimon).
+
+You are all set! Happy (secretive) chatting, enjoy doing everything from your favourite OS, Emacs!