To install the GNU Taler Debian packages, first ensure that you have
the right Debian distribution. At this time, the packages are built for
Sid, which means you should use a system which at least includes
unstable packages in its source list.  We recommend using APT pinning
to limit unstable packages to those explicitly requested. To do this,
set your ``/etc/apt/preferences`` as follows:

.. code-block::

   Package: *
   Pin: release a=stable
   Pin-Priority: 700

   Package: *
   Pin: release a=testing
   Pin-Priority: 650

   Package: *
   Pin: release a=unstable
   Pin-Priority: 600

   Package: *
   Pin: release l=Debian-Security
   Pin-Priority: 1000

A typical ``/etc/apt/sources.list`` file for this setup
which combines Debian stable with more recent packages
from testing and unstable would look like this:

.. code-block::

   deb http://ftp.ch.debian.org/debian/ buster main
   deb http://security.debian.org/debian-security buster/updates main
   deb http://ftp.ch.debian.org/debian/ testing main
   deb http://ftp.ch.debian.org/debian/ unstable main

Naturally, you may want to use different mirrors depending on your region.
Additionally, you must add a file to import the GNU Taler packages. Typically,
this is done by adding a file ``/etc/apt/sources.list.d/taler.list`` that
looks like this:

.. code-block::

   deb https://deb.taler.net/apt/debian sid main

Next, you must import the Taler Systems SA public package signing key
into your keyring and update the package lists:

.. code-block:: console

   # wget -O - https://taler.net/taler-systems.gpg.key | apt-key add -
   # apt update

.. note::

   You may want to verify the correctness of the Taler Systems key out-of-band.

Now your system is ready to install the official GNU Taler binary packages
using apt.