Installation
============

All versions of ``python-tuf`` can be installed from
`PyPI <https://pypi.org/project/tuf/>`_ with
`pip <https://pip.pypa.io/en/stable/>`_.

::

   python3 -m pip install tuf

By default tuf is installed as pure python package with limited cryptographic
abilities. See `Install with full cryptographic abilities`_ for more options.


Install with full cryptographic abilities
-----------------------------------------

Default installation supports signature verification only, using a pure Python
*ed25519* implementation. While this allows to operate a *basic client* on
almost any computing device, you will need additional cryptographic abilities
for *repository* code, i.e. key and signature generation, additional
algorithms, and more performant backends. Opt-in is available via
``securesystemslib``.

.. note::

   Please consult with underlying crypto backend installation docs --
   `cryptography <https://cryptography.io/en/latest/installation/>`_ and
   `pynacl <https://pynacl.readthedocs.io/en/latest/install/>`_  --
   for possible system dependencies.

::

   python3 -m pip securesystemslib[crypto,pynacl] tuf


Install for development
-----------------------

To install tuf in editable mode together with development dependencies,
`clone <https://docs.github.com/en/repositories/creating-and-managing-repositories/cloning-a-repository>`_ the
`python-tuf repository <https://github.com/theupdateframework/python-tuf>`_
from GitHub, change into the project root directory, and install with pip
(using `venv <https://docs.python.org/3/library/venv.html>`_ is recommended).

.. note::

   Development installation will `Install with full cryptographic abilities`_.
   Please check above for possible system dependencies.

::

   python3 -m pip install -r requirements/dev.txt


Verify release signatures
-------------------------

Releases on PyPI are signed with a maintainer key using
`gpg <https://gnupg.org/>`_  (see
`MAINTAINERS.txt <https://github.com/theupdateframework/python-tuf/blob/develop/docs/MAINTAINERS.txt>`_
for key fingerprints). Signatures can be downloaded from the
`GitHub release <https://github.com/theupdateframework/python-tuf/releases>`_
page (look for *\*.asc* files in the *Assets* section).

Below code shows how to verify the signature of a
`built <https://packaging.python.org/en/latest/glossary/#term-Built-Distribution>`_ distribution,
signed by the maintainer *Lukas Pühringer*. It works
alike for `source  <https://packaging.python.org/en/latest/glossary/#term-Source-Distribution-or-sdist>`_ distributions.

::

   # Get wheel from PyPI and signature from GitHub
   python3 -m pip download --no-deps tuf==0.20.0
   wget https://github.com/theupdateframework/python-tuf/releases/download/v0.20.0/tuf-0.20.0-py3-none-any.whl.asc

   # Get public key, compare fingerprint in MAINTAINERS.txt, and verify with gpg
   gpg --recv-keys 89A2AD3C07D962E8
   gpg --verify tuf-0.20.0-py3-none-any.whl.asc

   # Output:
   # gpg: assuming signed data in 'tuf-0.20.0-py3-none-any.whl'
   # gpg: Signature made Thu Dec 16 09:21:38 2021 CET
   # gpg:                using RSA key 8BA69B87D43BE294F23E812089A2AD3C07D962E8
   # gpg: Good signature from "Lukas Pühringer <lukas.puehringer@nyu.edu>" [ultimate]