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diff --git a/lang/python/doc/rst/gpgme-python-howto.rst b/lang/python/doc/rst/gpgme-python-howto.rst deleted file mode 100644 index 6f711091..00000000 --- a/lang/python/doc/rst/gpgme-python-howto.rst +++ /dev/null @@ -1,3330 +0,0 @@ -.. _intro: - -Introduction -============ - -+-----------------+------------------------------------------+ -| Version: | 0.1.5 | -+-----------------+------------------------------------------+ -| GPGME Version: | 1.13.0 | -+-----------------+------------------------------------------+ -| Author: | Ben McGinnes <[email protected]> | -+-----------------+------------------------------------------+ -| Author GPG Key: | DB4724E6FA4286C92B4E55C4321E4E2373590E5D | -+-----------------+------------------------------------------+ -| Language: | Australian English, British English | -+-----------------+------------------------------------------+ -| Language codes: | en-AU, en-GB, en | -+-----------------+------------------------------------------+ - -This document provides basic instruction in how to use the GPGME Python -bindings to programmatically leverage the GPGME library. - -.. _py2-vs-py3: - -Python 2 versus Python 3 ------------------------- - -Though the GPGME Python bindings themselves provide support for both -Python 2 and 3, the focus is unequivocally on Python 3 and specifically -from Python 3.4 and above. As a consequence all the examples and -instructions in this guide use Python 3 code. - -Much of it will work with Python 2, but much of it also deals with -Python 3 byte literals, particularly when reading and writing data. -Developers concentrating on Python 2.7, and possibly even 2.6, will need -to make the appropriate modifications to support the older string and -unicode types as opposed to bytes. - -There are multiple reasons for concentrating on Python 3; some of which -relate to the immediate integration of these bindings, some of which -relate to longer term plans for both GPGME and the python bindings and -some of which relate to the impending EOL period for Python 2.7. -Essentially, though, there is little value in tying the bindings to a -version of the language which is a dead end and the advantages offered -by Python 3 over Python 2 make handling the data types with which GPGME -deals considerably easier. - -.. _howto-python3-examples: - -Examples --------- - -All of the examples found in this document can be found as Python 3 -scripts in the ``lang/python/examples/howto`` directory. - -Unofficial Drafts ------------------ - -In addition to shipping with each release of GPGME, there is a section -on locations to read or download `draft editions <#draft-editions>`__ of -this document from at the end of it. These are unofficial versions -produced in between major releases. - -.. _new-stuff: - -What\'s New ------------ - -Full details of what is new are now available in the `What\'s -New <what-is-new.org>`__ file and archives of the preceding *What\'s -New* sections are available in the `What Was New <what-was-new>`__ file. - -.. _new-stuff-1-13-0: - -New in GPGME 1·13·0 -~~~~~~~~~~~~~~~~~~~ - -See the `What\'s New <what-is-new#new-stuff-1-13-0>`__ document for what -is new in version 1.13.0. - -.. _new-stuff-1-12-0: - -New in GPGME 1·12·0 -~~~~~~~~~~~~~~~~~~~ - -See the `What Was New <what-was-new#new-stuff-1-12-0>`__ document for -what was new in version 1.12.0. - -GPGME Concepts -============== - -.. _gpgme-c-api: - -A C API -------- - -Unlike many modern APIs with which programmers will be more familiar -with these days, the GPGME API is a C API. The API is intended for use -by C coders who would be able to access its features by including the -``gpgme.h`` header file with their own C source code and then access its -functions just as they would any other C headers. - -This is a very effective method of gaining complete access to the API -and in the most efficient manner possible. It does, however, have the -drawback that it cannot be directly used by other languages without some -means of providing an interface to those languages. This is where the -need for bindings in various languages stems. - -.. _gpgme-python-bindings: - -Python bindings ---------------- - -The Python bindings for GPGME provide a higher level means of accessing -the complete feature set of GPGME itself. It also provides a more -pythonic means of calling these API functions. - -The bindings are generated dynamically with SWIG and the copy of -``gpgme.h`` generated when GPGME is compiled. - -This means that a version of the Python bindings is fundamentally tied -to the exact same version of GPGME used to generate that copy of -``gpgme.h``. - -.. _gpgme-python-bindings-diffs: - -Difference between the Python bindings and other GnuPG Python packages ----------------------------------------------------------------------- - -There have been numerous attempts to add GnuPG support to Python over -the years. Some of the most well known are listed here, along with what -differentiates them. - -.. _diffs-python-gnupg: - -The python-gnupg package maintained by Vinay Sajip -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -This is arguably the most popular means of integrating GPG with Python. -The package utilises the ``subprocess`` module to implement wrappers for -the ``gpg`` and ``gpg2`` executables normally invoked on the command -line (``gpg.exe`` and ``gpg2.exe`` on Windows). - -The popularity of this package stemmed from its ease of use and -capability in providing the most commonly required features. - -Unfortunately it has been beset by a number of security issues in the -past; most of which stemmed from using unsafe methods of accessing the -command line via the ``subprocess`` calls. While some effort has been -made over the last two to three years (as of 2018) to mitigate this, -particularly by no longer providing shell access through those -subprocess calls, the wrapper is still somewhat limited in the scope of -its GnuPG features coverage. - -The python-gnupg package is available under the MIT license. - -.. _diffs-isis-gnupg: - -The gnupg package created and maintained by Isis Lovecruft -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -In 2015 Isis Lovecruft from the Tor Project forked and then -re-implemented the python-gnupg package as just gnupg. This new package -also relied on subprocess to call the ``gpg`` or ``gpg2`` binaries, but -did so somewhat more securely. - -The naming and version numbering selected for this package, however, -resulted in conflicts with the original python-gnupg and since its -functions were called in a different manner to python-gnupg, the release -of this package also resulted in a great deal of consternation when -people installed what they thought was an upgrade that subsequently -broke the code relying on it. - -The gnupg package is available under the GNU General Public License -version 3.0 (or any later version). - -.. _diffs-pyme: - -The PyME package maintained by Martin Albrecht -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -This package is the origin of these bindings, though they are somewhat -different now. For details of when and how the PyME package was folded -back into GPGME itself see the `Short History <short-history.org>`__ -document. [1]_ - -The PyME package was first released in 2002 and was also the first -attempt to implement a low level binding to GPGME. In doing so it -provided access to considerably more functionality than either the -``python-gnupg`` or ``gnupg`` packages. - -The PyME package is only available for Python 2.6 and 2.7. - -Porting the PyME package to Python 3.4 in 2015 is what resulted in it -being folded into the GPGME project and the current bindings are the end -result of that effort. - -The PyME package is available under the same dual licensing as GPGME -itself: the GNU General Public License version 2.0 (or any later -version) and the GNU Lesser General Public License version 2.1 (or any -later version). - -.. _gpgme-python-install: - -GPGME Python bindings installation -================================== - -.. _do-not-use-pypi: - -No PyPI -------- - -Most third-party Python packages and modules are available and -distributed through the Python Package Installer, known as PyPI. - -Due to the nature of what these bindings are and how they work, it is -infeasible to install the GPGME Python bindings in the same way. - -This is because the bindings use SWIG to dynamically generate C bindings -against ``gpgme.h`` and ``gpgme.h`` is generated from ``gpgme.h.in`` at -compile time when GPGME is built from source. Thus to include a package -in PyPI which actually built correctly would require either statically -built libraries for every architecture bundled with it or a full -implementation of C for each architecture. - -See the additional notes regarding `CFFI and SWIG <#snafu-cffi>`__ at -the end of this section for further details. - -.. _gpgme-python-requirements: - -Requirements ------------- - -The GPGME Python bindings only have three requirements: - -#. A suitable version of Python 2 or Python 3. With Python 2 that means - CPython 2.7 and with Python 3 that means CPython 3.4 or higher. -#. `SWIG <https://www.swig.org>`__. -#. GPGME itself. Which also means that all of GPGME\'s dependencies must - be installed too. - -.. _gpgme-python-recommendations: - -Recommended Additions -~~~~~~~~~~~~~~~~~~~~~ - -Though none of the following are absolute requirements, they are all -recommended for use with the Python bindings. In some cases these -recommendations refer to which version(s) of CPython to use the bindings -with, while others refer to third party modules which provide a -significant advantage in some way. - -#. If possible, use Python 3 instead of 2. -#. Favour a more recent version of Python since even 3.4 is due to reach - EOL soon. In production systems and services, Python 3.6 should be - robust enough to be relied on. -#. If possible add the following Python modules which are not part of - the standard library: - `Requests <http://docs.python-requests.org/en/latest/index.html>`__, - `Cython <https://cython.org/>`__, - `Pendulum <https://pendulum.eustace.io/>`__ and - `hkp4py <https://github.com/Selfnet/hkp4py>`__. - -Chances are quite high that at least the first one and maybe two of -those will already be installed. - -Note that, as with Cython, some of advanced use case scenarios will -bring with them additional requirements. Most of these will be fairly -well known and commonly installed ones, however, which are in many cases -likely to have already been installed on many systems or be familiar to -Python programmers. - -Installation ------------- - -Installing the Python bindings is effectively achieved by compiling and -installing GPGME itself. - -Once SWIG is installed with Python and all the dependencies for GPGME -are installed you only need to confirm that the version(s) of Python you -want the bindings installed for are in your ``$PATH``. - -By default GPGME will attempt to install the bindings for the most -recent or highest version number of Python 2 and Python 3 it detects in -``$PATH``. It specifically checks for the ``python`` and ``python3`` -executables first and then checks for specific version numbers. - -For Python 2 it checks for these executables in this order: ``python``, -``python2`` and ``python2.7``. - -For Python 3 it checks for these executables in this order: ``python3``, -``python3.7``, ``python3.6``, ``python3.5`` and ``python3.4``. [2]_ - -On systems where ``python`` is actually ``python3`` and not ``python2`` -it may be possible that ``python2`` may be overlooked, but there have -been no reports of that actually occurring as yet. - -In the three months or so since the release of Python 3.7.0 there has -been extensive testing and work with these bindings with no issues -specifically relating to the new version of Python or any of the new -features of either the language or the bindings. This has also been the -case with Python 3.7.1rc1. With that in mind and given the release of -Python 3.7.1 is scheduled for around the same time as GPGME 1.12.0, the -order of preferred Python versions has been changed to move Python 3.7 -ahead of Python 3.6. - -.. _install-gpgme: - -Installing GPGME -~~~~~~~~~~~~~~~~ - -See the GPGME ``README`` file for details of how to install GPGME from -source. - -.. _snafu: - -Known Issues ------------- - -There are a few known issues with the current build process and the -Python bindings. For the most part these are easily addressed should -they be encountered. - -.. _snafu-a-swig-of-this-builds-character: - -Breaking Builds -~~~~~~~~~~~~~~~ - -Occasionally when installing GPGME with the Python bindings included it -may be observed that the ``make`` portion of that process induces a -large very number of warnings and, eventually errors which end that part -of the build process. Yet following that with ``make check`` and -``make install`` appears to work seamlessly. - -The cause of this is related to the way SWIG needs to be called to -dynamically generate the C bindings for GPGME in the first place. So the -entire process will always produce ``lang/python/python2-gpg/`` and -``lang/python/python3-gpg/`` directories. These should contain the build -output generated during compilation, including the complete bindings and -module installed into ``site-packages``. - -Occasionally the errors in the early part or some other conflict (e.g. -not installing as **root** or **su**) may result in nothing being -installed to the relevant ``site-packages`` directory and the build -directory missing a lot of expected files. Even when this occurs, the -solution is actually quite simple and will always work. - -That solution is simply to run the following commands as either the -**root** user or prepended with ``sudo -H``\ [3]_ in the -``lang/python/`` directory: - -.. code:: shell - - /path/to/pythonX.Y setup.py build - /path/to/pythonX.Y setup.py build - /path/to/pythonX.Y setup.py install - -Yes, the build command does need to be run twice. Yes, you still need to -run the potentially failing or incomplete steps during the -``configure``, ``make`` and ``make install`` steps with installing -GPGME. This is because those steps generate a lot of essential files -needed, both by and in order to create, the bindings (including both the -``setup.py`` and ``gpgme.h`` files). - -#. IMPORTANT Note - - If specifying a selected number of languages to create bindings for, - try to leave Python last. Currently the majority of the other - language bindings are also preceding Python of either version when - listed alphabetically (not counting the Qt bindings). - - If Python is set to precede one of the other languages then it is - possible that the errors described here may interrupt the build - process before generating bindings for those other languages. In - these cases it may be preferable to configure all preferred language - bindings separately with alternative ``configure`` steps for GPGME - using the ``--enable-languages=$LANGUAGE`` option. - - Alternatively ``make`` (or ``gmake``, depending on your platform) may - be run with the the ``-k`` option, which tells make to keep going - even if errors are encountered. In that case the failure of one - language\'s set of bindings to build should not hamper another - language\'s bindings to build. - -.. _snafu-lessons-for-the-lazy: - -Reinstalling Responsibly -~~~~~~~~~~~~~~~~~~~~~~~~ - -Regardless of whether you\'re installing for one version of Python or -several, there will come a point where reinstallation is required. With -most Python module installations, the installed files go into the -relevant site-packages directory and are then forgotten about. Then the -module is upgraded, the new files are copied over the old and that\'s -the end of the matter. - -While the same is true of these bindings, there have been intermittent -issues observed on some platforms which have benefited significantly -from removing all the previous installations of the bindings before -installing the updated versions. - -Removing the previous version(s) is simply a matter of changing to the -relevant ``site-packages`` directory for the version of Python in -question and removing the ``gpg/`` directory and any accompanying -egg-info files for that module. - -In most cases this will require root or administration privileges on the -system, but the same is true of installing the module in the first -place. - -.. _snafu-the-full-monty: - -Multiple installations -~~~~~~~~~~~~~~~~~~~~~~ - -For a variety of reasons it may be either necessary or just preferable -to install the bindings to alternative installed Python versions which -meet the requirements of these bindings. - -On POSIX systems this will generally be most simply achieved by running -the manual installation commands (build, build, install) as described in -the previous section for each Python installation the bindings need to -be installed to. - -As per the SWIG documentation: the compilers, libraries and runtime used -to build GPGME and the Python Bindings **must** match those used to -compile Python itself, including the version number(s) (at least going -by major version numbers and probably minor numbers too). - -On most POSIX systems, including OS X, this will very likely be the case -in most, if not all, cases. - -Note that from GPGME -`1.12.1 <https://dev.gnupg.org/rMff6ff616aea6f59b7f2ce1176492850ecdf3851e>`__ -the default installation installs to each version of Python it can find -first. That is that it will currently install for the first copies of -Python versions 2.7, 3.4, 3.5, 3.6, 3.7 and 3.8 (dev branch) that it -finds. Usually this will be in the same prefix as GPGME itself, but is -dictated by the ``$PATH`` when the installation is performed. The above -instructions can still be performed on other python installations which -the installer does not find, including alternative prefixes. - -.. _snafu-runtime-not-funtime: - -Won\'t Work With Windows -~~~~~~~~~~~~~~~~~~~~~~~~ - -There are semi-regular reports of Windows users having considerable -difficulty in installing and using the Python bindings at all. Very -often, possibly even always, these reports come from Cygwin users and/or -MinGW users and/or Msys2 users. Though not all of them have been -confirmed, it appears that these reports have also come from people who -installed Python using the Windows installer files from the `Python -website <https://python.org>`__ (i.e. mostly MSI installers, sometimes -self-extracting ``.exe`` files). - -The Windows versions of Python are not built using Cygwin, MinGW or -Msys2; they\'re built using Microsoft Visual Studio. Furthermore the -version used is *considerably* more advanced than the version which -MinGW obtained a small number of files from many years ago in order to -be able to compile anything at all. Not only that, but there are changes -to the version of Visual Studio between some micro releases, though that -is is particularly the case with Python 2.7, since it has been kept -around far longer than it should have been. - -There are two theoretical solutions to this issue: - -#. Compile and install the GnuPG stack, including GPGME and the Python - bindings using the same version of Microsoft Visual Studio used by - the Python Foundation to compile the version of Python installed. - - If there are multiple versions of Python then this will need to be - done with each different version of Visual Studio used for those - versions of Python. - -#. Compile and install Python using the same tools used by choice, such - as MinGW or Msys2. - -Do **not** use the official Windows installer for Python unless -following the first method. - -In this type of situation it may even be for the best to accept that -there are less limitations on permissive software than free software and -simply opt to use a recent version of the Community Edition of Microsoft -Visual Studio to compile and build all of it, no matter what. - -Investigations into the extent or the limitations of this issue are -ongoing. - -The following table lists the version of Microsoft Visual Studio which -needs to be used when compiling GPGME and the Python bindings with each -version of the CPython binary released `for -Windows <https://www.python.org/downloads/windows/>`__: - -+---------+------------------------+------------------+ -| CPython | Microsoft product name | runtime filename | -+---------+------------------------+------------------+ -| 2.7.6 | Visual Studio 2008 | MSVCR90.DLL | -+---------+------------------------+------------------+ -| 3.4.0 | Visual Studio 2010 | MSVCR100.DLL | -+---------+------------------------+------------------+ -| 3.5.0 | Visual Studio 2015 | **see below** | -+---------+------------------------+------------------+ -| 3.6.0 | Visual Studio 2015 | **see below** | -+---------+------------------------+------------------+ -| 3.7.0 | Visual Studio 2017\* | **see below** | -+---------+------------------------+------------------+ - -It is important to note that MingW and Msys2 ship with the Visual C -runtime from Microsoft Visual Studio 2005 and are thus **incompatible** -with all the versions of CPython which can be used with the GPGME Python -bindings. - -It is also important to note that from CPython 3.5 onwards, the Python -Foundation has adopted the reworking of the Visual C runtime which was -performed for Visual Studio 2015 and aimed at resolving many of these -kinds of issues. Much greater detail on these issues and the correct -file(s) to link to are available from Matthew Brett\'s invaluable page, -`Using Microsoft Visual C with -Python <https://matthew-brett.github.io/pydagogue/python_msvc.html>`__. -It is also worth reading the Microsoft Developer Network blog post on -`the universal -CRT <http://blogs.msdn.com/b/vcblog/archive/2015/03/03/introducing-the-universal-crt.aspx>`__ -and Steve Dower\'s blog posts on Python extensions (`part -1 <http://stevedower.id.au/blog/building-for-python-3-5>`__ and `part -2 <http://stevedower.id.au/blog/building-for-python-3-5-part-two>`__). - -The second of those two posts by Steve Dower contains the details of -specific configuration options required for compiling anything to be -used with official CPython releases. In addition to those configuration -and compiler settings to use, the versions of Visual Studio prior to -Visual Studio 2015 did not support 64-bit systems by default. So -compiling a 64-bit version of these bindings for a 64-bit version of -CPython 2.7 or 3.4 requires additional work. - -In addition to the blog posts, the `Windows -compilers <https://wiki.python.org/moin/WindowsCompilers>`__ wiki page -on the CPython wiki is another essential reference on the relevant -versions of Visual Studio to use and the degree of compatibility with -CPython releases. - -Eventually someone will ask why there isn\'t an installable binary for -Windows, which the GPGME of the licenses do not preclude as long as the -source code is available in conjunction with such a release. - -The sheer number of versions of Visual Studio in conjunction with -differing configuration options depending on the target Windows version -and whether the architecture is 64-bit or 32-bit makes it difficult to -provide a correct binary installer for Windows users. At the bare -minimum doing so would require the GnuPG project compile ten different -versions of the bindings with each release; both 32-bit and 64-bit -versions for CPython 2.7 and 3.4, with 64-bit versions for both x86-64 -(i.e. Intel and AMD) and ARM architectures for CPython 3.5, 3.6, 3.7 and -later releases. That\'s the bare **minimum**, it\'d probably be higher. - -Additionally, with only a binary installation used in conjunction with -the CPython installer from ``python.org`` the advanced options available -which utilise `Cython <#cython>`__ will not be able to be used at all. -Cython depends on being able to compile the C code it generates and that -too would need to utilise a matching runtime to both the installed -version of CPython and these bindings in order to work with the -bindings. - -Considering all of that, what do we recommend? - -#. Use a recent version of CPython; at least 3.5, but ideally 3.6 or - later. - -#. Use Visual Studio 2015 or the standalone build tools for Visual - Studio 2017 (or later). - -#. Compile both CPython and GPGME with these bindings using the tools - selected in step 2. - -#. Ignore MingW, Msys2 and the official CPython binary installers. - -#. Be thankful the answer to this question wasn\'t simply to say - something like, "install Linux" or "install FreeBSD" (or even - Apple\'s OS X). - -.. _snafu-cffi: - -CFFI is the Best™ and GPGME should use it instead of SWIG -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -There are many reasons for favouring -`CFFI <https://cffi.readthedocs.io/en/latest/overview.html>`__ and -proponents of it are quite happy to repeat these things as if all it -would take to switch from SWIG to CFFI is repeating that list as if it -were a new concept. - -The fact is that there are things which Python\'s CFFI implementation -cannot handle in the GPGME C code. Beyond that there are features of -SWIG which are simply not available with CFFI at all. SWIG generates the -bindings to Python using the ``gpgme.h`` file, but that file is not a -single version shipped with each release, it too is generated when GPGME -is compiled. - -CFFI is currently unable to adapt to such a potentially mutable -codebase. If there were some means of applying SWIG\'s dynamic code -generation to produce the Python/CFFI API modes of accessing the GPGME -libraries (or the source source code directly), but such a thing does -not exist yet either and it currently appears that work is needed in at -least one of CFFI\'s dependencies before any of this can be addressed. - -So if you\'re a massive fan of CFFI; that\'s great, but if you want this -project to switch to CFFI then rather than just insisting that it -should, I\'d suggest you volunteer to bring CFFI up to the level this -project needs. - -If you\'re actually seriously considering doing so, then I\'d suggest -taking the ``gpgme-tool.c`` file in the GPGME ``src/`` directory and -getting that to work with any of the CFFI API methods (not the ABI -methods, they\'ll work with pretty much anything). When you start -running into trouble with \"ifdefs\" then you\'ll know what sort of -things are lacking. That doesn\'t even take into account the amount of -work saved via SWIG\'s code generation techniques either. - -.. _snafu-venv: - -Virtualised Environments -~~~~~~~~~~~~~~~~~~~~~~~~ - -It is fairly common practice amongst Python developers to, as much as -possible, use packages like virtualenv to keep various things that are -to be installed from interfering with each other. Given how much of the -GPGME bindings is often at odds with the usual pythonic way of doing -things, it stands to reason that this would be called into question too. - -As it happens the answer as to whether or not the bindings can be used -with virtualenv, the answer is both yes and no. - -In general we recommend installing to the relevant path and matching -prefix of GPGME itself. Which means that when GPGME, and ideally the -rest of the GnuPG stack, is installed to a prefix like ``/usr/local`` or -``/opt/local`` then the bindings would need to be installed to the main -Python installation and not a virtualised abstraction. Attempts to -separate the two in the past have been known to cause weird and -intermittent errors ranging from minor annoyances to complete failures -in the build process. - -As a consequence we only recommend building with and installing to the -main Python installations within the same prefix as GPGME is installed -to or which are found by GPGME\'s configuration stage immediately prior -to running the make commands. Which is exactly what the compiling and -installing process of GPGME does by default. - -Once that is done, however, it appears that a copy of the compiled -module may be installed into a virtualenv of the same major and minor -version matching the build. Alternatively it is possible to utilise a -``sites.pth`` file in the ``site-packages/`` directory of a virtualenv -installation, which links back to the system installations corresponding -directory in order to import anything installed system wide. This may or -may not be appropriate on a case by case basis. - -Though extensive testing of either of these options is not yet complete, -preliminary testing of them indicates that both are viable as long as -the main installation is complete. Which means that certain other -options normally restricted to virtual environments are also available, -including integration with pythonic test suites (e.g. -`pytest <https://docs.pytest.org/en/latest/index.html>`__) and other -large projects. - -That said, it is worth reiterating the warning regarding non-standard -installations. If one were to attempt to install the bindings only to a -virtual environment without somehow also including the full GnuPG stack -(or enough of it as to include GPGME) then it is highly likely that -errors would be encountered at some point and more than a little likely -that the build process itself would break. - -If a degree of separation from the main operating system is still -required in spite of these warnings, then consider other forms of -virtualisation. Either a virtual machine (e.g. -`VirtualBox <https://www.virtualbox.org/>`__), a hardware emulation -layer (e.g. `QEMU <https://www.qemu.org/>`__) or an application -container (e.g. `Docker <https://www.docker.com/why-docker>`__). - -Finally it should be noted that the limited tests conducted thus far -have been using the ``virtualenv`` command in a new directory to create -the virtual python environment. As opposed to the standard ``python3 --m venv`` and it is possible that this will make a difference depending -on the system and version of Python in use. Another option is to run the -command ``python3 -m virtualenv /path/to/install/virtual/thingy`` -instead. - -.. _snafu-docs: - -Post installation -~~~~~~~~~~~~~~~~~ - -Following installation it is recommended to move the -``post_installer.py`` script from the ``lang/python/examples/howto/`` -directory to the ``lang/python/`` directory and run it. This will fix or -restore files needed by Sphinx which may be removed during a -distribution build for release. It will also generate reST files from -Org mode files with Pandoc and generate Texinfo files from Org mode -files with GNU Emacs and Org mode (in batch mode). Additionally it will -fix the UTF-8 declaration line in the Texinfo files (Emacs expects -\"UTF-8\" to be \"utf-8\"). - -.. _howto-fund-a-mental: - -Fundamentals -============ - -Before we can get to the fun stuff, there are a few matters regarding -GPGME\'s design which hold true whether you\'re dealing with the C code -directly or these Python bindings. - -.. _no-rest-for-the-wicked: - -No REST -------- - -The first part of which is or will be fairly blatantly obvious upon -viewing the first example, but it\'s worth reiterating anyway. That -being that this API is **not** a REST API. Nor indeed could it ever be -one. - -Most, if not all, Python programmers (and not just Python programmers) -know how easy it is to work with a RESTful API. In fact they\'ve become -so popular that many other APIs attempt to emulate REST-like behaviour -as much as they are able. Right down to the use of JSON formatted output -to facilitate the use of their API without having to retrain developers. - -This API does not do that. It would not be able to do that and also -provide access to the entire C API on which it\'s built. It does, -however, provide a very pythonic interface on top of the direct bindings -and it\'s this pythonic layer that this HOWTO deals with. - -.. _howto-get-context: - -Context -------- - -One of the reasons which prevents this API from being RESTful is that -most operations require more than one instruction to the API to perform -the task. Sure, there are certain functions which can be performed -simultaneously, particularly if the result known or strongly anticipated -(e.g. selecting and encrypting to a key known to be in the public -keybox). - -There are many more, however, which cannot be manipulated so readily: -they must be performed in a specific sequence and the result of one -operation has a direct bearing on the outcome of subsequent operations. -Not merely by generating an error either. - -When dealing with this type of persistent state on the web, full of both -the RESTful and REST-like, it\'s most commonly referred to as a session. -In GPGME, however, it is called a context and every operation type has -one. - -.. _howto-keys: - -Working with keys -================= - -.. _howto-keys-selection: - -Key selection -------------- - -Selecting keys to encrypt to or to sign with will be a common occurrence -when working with GPGMe and the means available for doing so are quite -simple. - -They do depend on utilising a Context; however once the data is recorded -in another variable, that Context does not need to be the same one which -subsequent operations are performed. - -The easiest way to select a specific key is by searching for that key\'s -key ID or fingerprint, preferably the full fingerprint without any -spaces in it. A long key ID will probably be okay, but is not advised -and short key IDs are already a problem with some being generated to -match specific patterns. It does not matter whether the pattern is upper -or lower case. - -So this is the best method: - -.. code:: python - - import gpg - - k = gpg.Context().keylist(pattern="258E88DCBD3CD44D8E7AB43F6ECB6AF0DEADBEEF") - keys = list(k) - -This is passable and very likely to be common: - -.. code:: python - - import gpg - - k = gpg.Context().keylist(pattern="0x6ECB6AF0DEADBEEF") - keys = list(k) - -And this is a really bad idea: - -.. code:: python - - import gpg - - k = gpg.Context().keylist(pattern="0xDEADBEEF") - keys = list(k) - -Alternatively it may be that the intention is to create a list of keys -which all match a particular search string. For instance all the -addresses at a particular domain, like this: - -.. code:: python - - import gpg - - ncsc = gpg.Context().keylist(pattern="ncsc.mil") - nsa = list(ncsc) - -.. _howto-keys-counting: - -Counting keys -~~~~~~~~~~~~~ - -Counting the number of keys in your public keybox (``pubring.kbx``), the -format which has superseded the old keyring format (``pubring.gpg`` and -``secring.gpg``), or the number of secret keys is a very simple task. - -.. code:: python - - import gpg - - c = gpg.Context() - seckeys = c.keylist(pattern=None, secret=True) - pubkeys = c.keylist(pattern=None, secret=False) - - seclist = list(seckeys) - secnum = len(seclist) - - publist = list(pubkeys) - pubnum = len(publist) - - print(""" - Number of secret keys: {0} - Number of public keys: {1} - """.format(secnum, pubnum)) - -NOTE: The `Cython <#cython>`__ introduction in the `Advanced and -Experimental <#advanced-use>`__ section uses this same key counting code -with Cython to demonstrate some areas where Cython can improve -performance even with the bindings. Users with large public keyrings or -keyboxes, for instance, should consider these options if they are -comfortable with using Cython. - -.. _howto-get-key: - -Get key -------- - -An alternative method of getting a single key via its fingerprint is -available directly within a Context with ``Context().get_key``. This is -the preferred method of selecting a key in order to modify it, sign or -certify it and for obtaining relevant data about a single key as a part -of other functions; when verifying a signature made by that key, for -instance. - -By default this method will select public keys, but it can select secret -keys as well. - -This first example demonstrates selecting the current key of Werner -Koch, which is due to expire at the end of 2018: - -.. code:: python - - import gpg - - fingerprint = "80615870F5BAD690333686D0F2AD85AC1E42B367" - key = gpg.Context().get_key(fingerprint) - -Whereas this example demonstrates selecting the author\'s current key -with the ``secret`` key word argument set to ``True``: - -.. code:: python - - import gpg - - fingerprint = "DB4724E6FA4286C92B4E55C4321E4E2373590E5D" - key = gpg.Context().get_key(fingerprint, secret=True) - -It is, of course, quite possible to select expired, disabled and revoked -keys with this function, but only to effectively display information -about those keys. - -It is also possible to use both unicode or string literals and byte -literals with the fingerprint when getting a key in this way. - -.. _howto-import-key: - -Importing keys --------------- - -Importing keys is possible with the ``key_import()`` method and takes -one argument which is a bytes literal object containing either the -binary or ASCII armoured key data for one or more keys. - -The following example retrieves one or more keys from the SKS keyservers -via the web using the requests module. Since requests returns the -content as a bytes literal object, we can then use that directly to -import the resulting data into our keybox. - -.. code:: python - - import gpg - import os.path - import requests - - c = gpg.Context() - url = "https://sks-keyservers.net/pks/lookup" - pattern = input("Enter the pattern to search for key or user IDs: ") - payload = {"op": "get", "search": pattern} - - r = requests.get(url, verify=True, params=payload) - result = c.key_import(r.content) - - if result is not None and hasattr(result, "considered") is False: - print(result) - elif result is not None and hasattr(result, "considered") is True: - num_keys = len(result.imports) - new_revs = result.new_revocations - new_sigs = result.new_signatures - new_subs = result.new_sub_keys - new_uids = result.new_user_ids - new_scrt = result.secret_imported - nochange = result.unchanged - print(""" - The total number of keys considered for import was: {0} - - Number of keys revoked: {1} - Number of new signatures: {2} - Number of new subkeys: {3} - Number of new user IDs: {4} - Number of new secret keys: {5} - Number of unchanged keys: {6} - - The key IDs for all considered keys were: - """.format(num_keys, new_revs, new_sigs, new_subs, new_uids, new_scrt, - nochange)) - for i in range(num_keys): - print("{0}\n".format(result.imports[i].fpr)) - else: - pass - -NOTE: When searching for a key ID of any length or a fingerprint -(without spaces), the SKS servers require the the leading ``0x`` -indicative of hexadecimal be included. Also note that the old short key -IDs (e.g. ``0xDEADBEEF``) should no longer be used due to the relative -ease by which such key IDs can be reproduced, as demonstrated by the -Evil32 Project in 2014 (which was subsequently exploited in 2016). - -Testing for whether a string in any given search is or may be a -hexadecimal value which may be missing the leading ``0x`` is a simple -matter of using a try/except statement which attempts to convert the -string as hex to an integer and then back to hex; then using that to -search with. Raising a ValueError simply results in treating the string -as a string. This is the method and logic utilised in the -``import-keys-hkp.py`` script (see below). - -.. _import-protonmail: - -Working with ProtonMail -~~~~~~~~~~~~~~~~~~~~~~~ - -Here is a variation on the example above which checks the constrained -ProtonMail keyserver for ProtonMail public keys. - -.. code:: python - - import gpg - import requests - import sys - - print(""" - This script searches the ProtonMail key server for the specified key and - imports it. - """) - - c = gpg.Context(armor=True) - url = "https://api.protonmail.ch/pks/lookup" - ksearch = [] - - if len(sys.argv) >= 2: - keyterm = sys.argv[1] - else: - keyterm = input("Enter the key ID, UID or search string: ") - - if keyterm.count("@") == 2 and keyterm.startswith("@") is True: - ksearch.append(keyterm[1:]) - ksearch.append(keyterm[1:]) - ksearch.append(keyterm[1:]) - elif keyterm.count("@") == 1 and keyterm.startswith("@") is True: - ksearch.append("{0}@protonmail.com".format(keyterm[1:])) - ksearch.append("{0}@protonmail.ch".format(keyterm[1:])) - ksearch.append("{0}@pm.me".format(keyterm[1:])) - elif keyterm.count("@") == 0: - ksearch.append("{0}@protonmail.com".format(keyterm)) - ksearch.append("{0}@protonmail.ch".format(keyterm)) - ksearch.append("{0}@pm.me".format(keyterm)) - elif keyterm.count("@") == 2 and keyterm.startswith("@") is False: - uidlist = keyterm.split("@") - for uid in uidlist: - ksearch.append("{0}@protonmail.com".format(uid)) - ksearch.append("{0}@protonmail.ch".format(uid)) - ksearch.append("{0}@pm.me".format(uid)) - elif keyterm.count("@") > 2: - uidlist = keyterm.split("@") - for uid in uidlist: - ksearch.append("{0}@protonmail.com".format(uid)) - ksearch.append("{0}@protonmail.ch".format(uid)) - ksearch.append("{0}@pm.me".format(uid)) - else: - ksearch.append(keyterm) - - for k in ksearch: - payload = {"op": "get", "search": k} - try: - r = requests.get(url, verify=True, params=payload) - if r.ok is True: - result = c.key_import(r.content) - elif r.ok is False: - result = r.content - except Exception as e: - result = None - - if result is not None and hasattr(result, "considered") is False: - print("{0} for {1}".format(result.decode(), k)) - elif result is not None and hasattr(result, "considered") is True: - num_keys = len(result.imports) - new_revs = result.new_revocations - new_sigs = result.new_signatures - new_subs = result.new_sub_keys - new_uids = result.new_user_ids - new_scrt = result.secret_imported - nochange = result.unchanged - print(""" - The total number of keys considered for import was: {0} - - With UIDs wholely or partially matching the following string: - - {1} - - Number of keys revoked: {2} - Number of new signatures: {3} - Number of new subkeys: {4} - Number of new user IDs: {5} - Number of new secret keys: {6} - Number of unchanged keys: {7} - - The key IDs for all considered keys were: - """.format(num_keys, k, new_revs, new_sigs, new_subs, new_uids, new_scrt, - nochange)) - for i in range(num_keys): - print(result.imports[i].fpr) - print("") - elif result is None: - print(e) - -Both the above example, -`pmkey-import.py <../examples/howto/pmkey-import.py>`__, and a version -which prompts for an alternative GnuPG home directory, -`pmkey-import-alt.py <../examples/howto/pmkey-import-alt.py>`__, are -available with the other examples and are executable scripts. - -Note that while the ProtonMail servers are based on the SKS servers, -their server is related more to their API and is not feature complete by -comparison to the servers in the SKS pool. One notable difference being -that the ProtonMail server does not permit non ProtonMail users to -update their own keys, which could be a vector for attacking ProtonMail -users who may not receive a key\'s revocation if it had been -compromised. - -.. _import-hkp4py: - -Importing with HKP for Python -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -Performing the same tasks with the `hkp4py -module <https://github.com/Selfnet/hkp4py>`__ (available via PyPI) is -not too much different, but does provide a number of options of benefit -to end users. Not least of which being the ability to perform some -checks on a key before importing it or not. For instance it may be the -policy of a site or project to only import keys which have not been -revoked. The hkp4py module permits such checks prior to the importing of -the keys found. - -.. code:: python - - import gpg - import hkp4py - import sys - - c = gpg.Context() - server = hkp4py.KeyServer("hkps://hkps.pool.sks-keyservers.net") - results = [] - keys = [] - - if len(sys.argv) > 2: - pattern = " ".join(sys.argv[1:]) - elif len(sys.argv) == 2: - pattern = sys.argv[1] - else: - pattern = input("Enter the pattern to search for keys or user IDs: ") - - - if pattern is not None: - try: - key = server.search(hex(int(pattern, 16))) - keyed = True - except ValueError as ve: - key = server.search(pattern) - keyed = False - - if key is not None: - keys.append(key[0]) - if keyed is True: - try: - fob = server.search(pattern) - except: - fob = None - if fob is not None: - keys.append(fob[0]) - else: - pass - else: - pass - - for logrus in pattern.split(): - try: - key = server.search(hex(int(logrus, 16))) - hexed = True - except ValueError as ve: - key = server.search(logrus) - hexed = False - - if key is not None: - keys.append(key[0]) - if hexed is True: - try: - fob = server.search(logrus) - except: - fob = None - if fob is not None: - keys.append(fob[0]) - else: - pass - else: - pass - - - if len(keys) > 0: - for key in keys: - import_result = c.key_import(key.key_blob) - results.append(import_result) - - for result in results: - if result is not None and hasattr(result, "considered") is False: - print(result) - elif result is not None and hasattr(result, "considered") is True: - num_keys = len(result.imports) - new_revs = result.new_revocations - new_sigs = result.new_signatures - new_subs = result.new_sub_keys - new_uids = result.new_user_ids - new_scrt = result.secret_imported - nochange = result.unchanged - print(""" - The total number of keys considered for import was: {0} - - Number of keys revoked: {1} - Number of new signatures: {2} - Number of new subkeys: {3} - Number of new user IDs: {4} - Number of new secret keys: {5} - Number of unchanged keys: {6} - - The key IDs for all considered keys were: - """.format(num_keys, new_revs, new_sigs, new_subs, new_uids, new_scrt, - nochange)) - for i in range(num_keys): - print(result.imports[i].fpr) - print("") - else: - pass - -Since the hkp4py module handles multiple keys just as effectively as one -(``keys`` is a list of responses per matching key), the example above is -able to do a little bit more with the returned data before anything is -actually imported. - -.. _import-protonmail-hkp4py: - -Importing from ProtonMail with HKP for Python -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -Though this can provide certain benefits even when working with -ProtonMail, the scope is somewhat constrained there due to the -limitations of the ProtonMail keyserver. - -For instance, searching the SKS keyserver pool for the term \"gnupg\" -produces hundreds of results from any time the word appears in any part -of a user ID. Performing the same search on the ProtonMail keyserver -returns zero results, even though there are at least two test accounts -which include it as part of the username. - -The cause of this discrepancy is the deliberate configuration of that -server by ProtonMail to require an exact match of the full email address -of the ProtonMail user whose key is being requested. Presumably this is -intended to reduce breaches of privacy of their users as an email -address must already be known before a key for that address can be -obtained. - -#. Import from ProtonMail via HKP for Python Example no. 1 - - The following script is available with the rest of the examples under - the somewhat less than original name, ``pmkey-import-hkp.py``. - - .. code:: python - - import gpg - import hkp4py - import os.path - import sys - - print(""" - This script searches the ProtonMail key server for the specified key and - imports it. - - Usage: pmkey-import-hkp.py [search strings] - """) - - c = gpg.Context(armor=True) - server = hkp4py.KeyServer("hkps://api.protonmail.ch") - keyterms = [] - ksearch = [] - allkeys = [] - results = [] - paradox = [] - homeless = None - - if len(sys.argv) > 2: - keyterms = sys.argv[1:] - elif len(sys.argv) == 2: - keyterm = sys.argv[1] - keyterms.append(keyterm) - else: - key_term = input("Enter the key ID, UID or search string: ") - keyterms = key_term.split() - - for keyterm in keyterms: - if keyterm.count("@") == 2 and keyterm.startswith("@") is True: - ksearch.append(keyterm[1:]) - ksearch.append(keyterm[1:]) - ksearch.append(keyterm[1:]) - elif keyterm.count("@") == 1 and keyterm.startswith("@") is True: - ksearch.append("{0}@protonmail.com".format(keyterm[1:])) - ksearch.append("{0}@protonmail.ch".format(keyterm[1:])) - ksearch.append("{0}@pm.me".format(keyterm[1:])) - elif keyterm.count("@") == 0: - ksearch.append("{0}@protonmail.com".format(keyterm)) - ksearch.append("{0}@protonmail.ch".format(keyterm)) - ksearch.append("{0}@pm.me".format(keyterm)) - elif keyterm.count("@") == 2 and keyterm.startswith("@") is False: - uidlist = keyterm.split("@") - for uid in uidlist: - ksearch.append("{0}@protonmail.com".format(uid)) - ksearch.append("{0}@protonmail.ch".format(uid)) - ksearch.append("{0}@pm.me".format(uid)) - elif keyterm.count("@") > 2: - uidlist = keyterm.split("@") - for uid in uidlist: - ksearch.append("{0}@protonmail.com".format(uid)) - ksearch.append("{0}@protonmail.ch".format(uid)) - ksearch.append("{0}@pm.me".format(uid)) - else: - ksearch.append(keyterm) - - for k in ksearch: - print("Checking for key for: {0}".format(k)) - try: - keys = server.search(k) - if isinstance(keys, list) is True: - for key in keys: - allkeys.append(key) - try: - import_result = c.key_import(key.key_blob) - except Exception as e: - import_result = c.key_import(key.key) - else: - paradox.append(keys) - import_result = None - except Exception as e: - import_result = None - results.append(import_result) - - for result in results: - if result is not None and hasattr(result, "considered") is False: - print("{0} for {1}".format(result.decode(), k)) - elif result is not None and hasattr(result, "considered") is True: - num_keys = len(result.imports) - new_revs = result.new_revocations - new_sigs = result.new_signatures - new_subs = result.new_sub_keys - new_uids = result.new_user_ids - new_scrt = result.secret_imported - nochange = result.unchanged - print(""" - The total number of keys considered for import was: {0} - - With UIDs wholely or partially matching the following string: - - {1} - - Number of keys revoked: {2} - Number of new signatures: {3} - Number of new subkeys: {4} - Number of new user IDs: {5} - Number of new secret keys: {6} - Number of unchanged keys: {7} - - The key IDs for all considered keys were: - """.format(num_keys, k, new_revs, new_sigs, new_subs, new_uids, new_scrt, - nochange)) - for i in range(num_keys): - print(result.imports[i].fpr) - print("") - elif result is None: - pass - -#. Import from ProtonMail via HKP for Python Example no. 2 - - Like its counterpart above, this script can also be found with the - rest of the examples, by the name pmkey-import-hkp-alt.py. - - With this script a modicum of effort has been made to treat anything - passed as a ``homedir`` which either does not exist or which is not a - directory, as also being a pssible user ID to check for. It\'s not - guaranteed to pick up on all such cases, but it should cover most of - them. - - .. code:: python - - import gpg - import hkp4py - import os.path - import sys - - print(""" - This script searches the ProtonMail key server for the specified key and - imports it. Optionally enables specifying a different GnuPG home directory. - - Usage: pmkey-import-hkp.py [homedir] [search string] - or: pmkey-import-hkp.py [search string] - """) - - c = gpg.Context(armor=True) - server = hkp4py.KeyServer("hkps://api.protonmail.ch") - keyterms = [] - ksearch = [] - allkeys = [] - results = [] - paradox = [] - homeless = None - - if len(sys.argv) > 3: - homedir = sys.argv[1] - keyterms = sys.argv[2:] - elif len(sys.argv) == 3: - homedir = sys.argv[1] - keyterm = sys.argv[2] - keyterms.append(keyterm) - elif len(sys.argv) == 2: - homedir = "" - keyterm = sys.argv[1] - keyterms.append(keyterm) - else: - keyterm = input("Enter the key ID, UID or search string: ") - homedir = input("Enter the GPG configuration directory path (optional): ") - keyterms.append(keyterm) - - if len(homedir) == 0: - homedir = None - homeless = False - - if homedir is not None: - if homedir.startswith("~"): - if os.path.exists(os.path.expanduser(homedir)) is True: - if os.path.isdir(os.path.expanduser(homedir)) is True: - c.home_dir = os.path.realpath(os.path.expanduser(homedir)) - else: - homeless = True - else: - homeless = True - elif os.path.exists(os.path.realpath(homedir)) is True: - if os.path.isdir(os.path.realpath(homedir)) is True: - c.home_dir = os.path.realpath(homedir) - else: - homeless = True - else: - homeless = True - - # First check to see if the homedir really is a homedir and if not, treat it as - # a search string. - if homeless is True: - keyterms.append(homedir) - c.home_dir = None - else: - pass - - for keyterm in keyterms: - if keyterm.count("@") == 2 and keyterm.startswith("@") is True: - ksearch.append(keyterm[1:]) - ksearch.append(keyterm[1:]) - ksearch.append(keyterm[1:]) - elif keyterm.count("@") == 1 and keyterm.startswith("@") is True: - ksearch.append("{0}@protonmail.com".format(keyterm[1:])) - ksearch.append("{0}@protonmail.ch".format(keyterm[1:])) - ksearch.append("{0}@pm.me".format(keyterm[1:])) - elif keyterm.count("@") == 0: - ksearch.append("{0}@protonmail.com".format(keyterm)) - ksearch.append("{0}@protonmail.ch".format(keyterm)) - ksearch.append("{0}@pm.me".format(keyterm)) - elif keyterm.count("@") == 2 and keyterm.startswith("@") is False: - uidlist = keyterm.split("@") - for uid in uidlist: - ksearch.append("{0}@protonmail.com".format(uid)) - ksearch.append("{0}@protonmail.ch".format(uid)) - ksearch.append("{0}@pm.me".format(uid)) - elif keyterm.count("@") > 2: - uidlist = keyterm.split("@") - for uid in uidlist: - ksearch.append("{0}@protonmail.com".format(uid)) - ksearch.append("{0}@protonmail.ch".format(uid)) - ksearch.append("{0}@pm.me".format(uid)) - else: - ksearch.append(keyterm) - - for k in ksearch: - print("Checking for key for: {0}".format(k)) - try: - keys = server.search(k) - if isinstance(keys, list) is True: - for key in keys: - allkeys.append(key) - try: - import_result = c.key_import(key.key_blob) - except Exception as e: - import_result = c.key_import(key.key) - else: - paradox.append(keys) - import_result = None - except Exception as e: - import_result = None - results.append(import_result) - - for result in results: - if result is not None and hasattr(result, "considered") is False: - print("{0} for {1}".format(result.decode(), k)) - elif result is not None and hasattr(result, "considered") is True: - num_keys = len(result.imports) - new_revs = result.new_revocations - new_sigs = result.new_signatures - new_subs = result.new_sub_keys - new_uids = result.new_user_ids - new_scrt = result.secret_imported - nochange = result.unchanged - print(""" - The total number of keys considered for import was: {0} - - With UIDs wholely or partially matching the following string: - - {1} - - Number of keys revoked: {2} - Number of new signatures: {3} - Number of new subkeys: {4} - Number of new user IDs: {5} - Number of new secret keys: {6} - Number of unchanged keys: {7} - - The key IDs for all considered keys were: - """.format(num_keys, k, new_revs, new_sigs, new_subs, new_uids, new_scrt, - nochange)) - for i in range(num_keys): - print(result.imports[i].fpr) - print("") - elif result is None: - pass - -.. _howto-export-key: - -Exporting keys --------------- - -Exporting keys remains a reasonably simple task, but has been separated -into three different functions for the OpenPGP cryptographic engine. Two -of those functions are for exporting public keys and the third is for -exporting secret keys. - -.. _howto-export-public-key: - -Exporting public keys -~~~~~~~~~~~~~~~~~~~~~ - -There are two methods of exporting public keys, both of which are very -similar to the other. The default method, ``key_export()``, will export -a public key or keys matching a specified pattern as normal. The -alternative, the ``key_export_minimal()`` method, will do the same thing -except producing a minimised output with extra signatures and third -party signatures or certifications removed. - -.. code:: python - - import gpg - import os.path - import sys - - print(""" - This script exports one or more public keys. - """) - - c = gpg.Context(armor=True) - - if len(sys.argv) >= 4: - keyfile = sys.argv[1] - logrus = sys.argv[2] - homedir = sys.argv[3] - elif len(sys.argv) == 3: - keyfile = sys.argv[1] - logrus = sys.argv[2] - homedir = input("Enter the GPG configuration directory path (optional): ") - elif len(sys.argv) == 2: - keyfile = sys.argv[1] - logrus = input("Enter the UID matching the key(s) to export: ") - homedir = input("Enter the GPG configuration directory path (optional): ") - else: - keyfile = input("Enter the path and filename to save the secret key to: ") - logrus = input("Enter the UID matching the key(s) to export: ") - homedir = input("Enter the GPG configuration directory path (optional): ") - - if homedir.startswith("~"): - if os.path.exists(os.path.expanduser(homedir)) is True: - c.home_dir = os.path.expanduser(homedir) - else: - pass - elif os.path.exists(homedir) is True: - c.home_dir = homedir - else: - pass - - try: - result = c.key_export(pattern=logrus) - except: - result = c.key_export(pattern=None) - - if result is not None: - with open(keyfile, "wb") as f: - f.write(result) - else: - pass - -It should be noted that the result will only return ``None`` when a -search pattern has been entered, but has not matched any keys. When the -search pattern itself is set to ``None`` this triggers the exporting of -the entire public keybox. - -.. code:: python - - import gpg - import os.path - import sys - - print(""" - This script exports one or more public keys in minimised form. - """) - - c = gpg.Context(armor=True) - - if len(sys.argv) >= 4: - keyfile = sys.argv[1] - logrus = sys.argv[2] - homedir = sys.argv[3] - elif len(sys.argv) == 3: - keyfile = sys.argv[1] - logrus = sys.argv[2] - homedir = input("Enter the GPG configuration directory path (optional): ") - elif len(sys.argv) == 2: - keyfile = sys.argv[1] - logrus = input("Enter the UID matching the key(s) to export: ") - homedir = input("Enter the GPG configuration directory path (optional): ") - else: - keyfile = input("Enter the path and filename to save the secret key to: ") - logrus = input("Enter the UID matching the key(s) to export: ") - homedir = input("Enter the GPG configuration directory path (optional): ") - - if homedir.startswith("~"): - if os.path.exists(os.path.expanduser(homedir)) is True: - c.home_dir = os.path.expanduser(homedir) - else: - pass - elif os.path.exists(homedir) is True: - c.home_dir = homedir - else: - pass - - try: - result = c.key_export_minimal(pattern=logrus) - except: - result = c.key_export_minimal(pattern=None) - - if result is not None: - with open(keyfile, "wb") as f: - f.write(result) - else: - pass - -.. _howto-export-secret-key: - -Exporting secret keys -~~~~~~~~~~~~~~~~~~~~~ - -Exporting secret keys is, functionally, very similar to exporting public -keys; save for the invocation of ``pinentry`` via ``gpg-agent`` in order -to securely enter the key\'s passphrase and authorise the export. - -The following example exports the secret key to a file which is then set -with the same permissions as the output files created by the command -line secret key export options. - -.. code:: python - - import gpg - import os - import os.path - import sys - - print(""" - This script exports one or more secret keys. - - The gpg-agent and pinentry are invoked to authorise the export. - """) - - c = gpg.Context(armor=True) - - if len(sys.argv) >= 4: - keyfile = sys.argv[1] - logrus = sys.argv[2] - homedir = sys.argv[3] - elif len(sys.argv) == 3: - keyfile = sys.argv[1] - logrus = sys.argv[2] - homedir = input("Enter the GPG configuration directory path (optional): ") - elif len(sys.argv) == 2: - keyfile = sys.argv[1] - logrus = input("Enter the UID matching the secret key(s) to export: ") - homedir = input("Enter the GPG configuration directory path (optional): ") - else: - keyfile = input("Enter the path and filename to save the secret key to: ") - logrus = input("Enter the UID matching the secret key(s) to export: ") - homedir = input("Enter the GPG configuration directory path (optional): ") - - if len(homedir) == 0: - homedir = None - elif homedir.startswith("~"): - userdir = os.path.expanduser(homedir) - if os.path.exists(userdir) is True: - homedir = os.path.realpath(userdir) - else: - homedir = None - else: - homedir = os.path.realpath(homedir) - - if os.path.exists(homedir) is False: - homedir = None - else: - if os.path.isdir(homedir) is False: - homedir = None - else: - pass - - if homedir is not None: - c.home_dir = homedir - else: - pass - - try: - result = c.key_export_secret(pattern=logrus) - except: - result = c.key_export_secret(pattern=None) - - if result is not None: - with open(keyfile, "wb") as f: - f.write(result) - os.chmod(keyfile, 0o600) - else: - pass - -Alternatively the approach of the following script can be used. This -longer example saves the exported secret key(s) in files in the GnuPG -home directory, in addition to setting the file permissions as only -readable and writable by the user. It also exports the secret key(s) -twice in order to output both GPG binary (``.gpg``) and ASCII armoured -(``.asc``) files. - -.. code:: python - - import gpg - import os - import os.path - import subprocess - import sys - - print(""" - This script exports one or more secret keys as both ASCII armored and binary - file formats, saved in files within the user's GPG home directory. - - The gpg-agent and pinentry are invoked to authorise the export. - """) - - if sys.platform == "win32": - gpgconfcmd = "gpgconf.exe --list-dirs homedir" - else: - gpgconfcmd = "gpgconf --list-dirs homedir" - - a = gpg.Context(armor=True) - b = gpg.Context() - c = gpg.Context() - - if len(sys.argv) >= 4: - keyfile = sys.argv[1] - logrus = sys.argv[2] - homedir = sys.argv[3] - elif len(sys.argv) == 3: - keyfile = sys.argv[1] - logrus = sys.argv[2] - homedir = input("Enter the GPG configuration directory path (optional): ") - elif len(sys.argv) == 2: - keyfile = sys.argv[1] - logrus = input("Enter the UID matching the secret key(s) to export: ") - homedir = input("Enter the GPG configuration directory path (optional): ") - else: - keyfile = input("Enter the filename to save the secret key to: ") - logrus = input("Enter the UID matching the secret key(s) to export: ") - homedir = input("Enter the GPG configuration directory path (optional): ") - - if len(homedir) == 0: - homedir = None - elif homedir.startswith("~"): - userdir = os.path.expanduser(homedir) - if os.path.exists(userdir) is True: - homedir = os.path.realpath(userdir) - else: - homedir = None - else: - homedir = os.path.realpath(homedir) - - if os.path.exists(homedir) is False: - homedir = None - else: - if os.path.isdir(homedir) is False: - homedir = None - else: - pass - - if homedir is not None: - c.home_dir = homedir - else: - pass - - if c.home_dir is not None: - if c.home_dir.endswith("/"): - gpgfile = "{0}{1}.gpg".format(c.home_dir, keyfile) - ascfile = "{0}{1}.asc".format(c.home_dir, keyfile) - else: - gpgfile = "{0}/{1}.gpg".format(c.home_dir, keyfile) - ascfile = "{0}/{1}.asc".format(c.home_dir, keyfile) - else: - if os.path.exists(os.environ["GNUPGHOME"]) is True: - hd = os.environ["GNUPGHOME"] - else: - try: - hd = subprocess.getoutput(gpgconfcmd) - except: - process = subprocess.Popen(gpgconfcmd.split(), - stdout=subprocess.PIPE) - procom = process.communicate() - if sys.version_info[0] == 2: - hd = procom[0].strip() - else: - hd = procom[0].decode().strip() - gpgfile = "{0}/{1}.gpg".format(hd, keyfile) - ascfile = "{0}/{1}.asc".format(hd, keyfile) - - try: - a_result = a.key_export_secret(pattern=logrus) - b_result = b.key_export_secret(pattern=logrus) - except: - a_result = a.key_export_secret(pattern=None) - b_result = b.key_export_secret(pattern=None) - - if a_result is not None: - with open(ascfile, "wb") as f: - f.write(a_result) - os.chmod(ascfile, 0o600) - else: - pass - - if b_result is not None: - with open(gpgfile, "wb") as f: - f.write(b_result) - os.chmod(gpgfile, 0o600) - else: - pass - -.. _howto-send-public-key: - -Sending public keys to the SKS Keyservers -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -As with the previous section on importing keys, the ``hkp4py`` module -adds another option with exporting keys in order to send them to the -public keyservers. - -The following example demonstrates how this may be done. - -.. code:: python - - import gpg - import hkp4py - import os.path - import sys - - print(""" - This script sends one or more public keys to the SKS keyservers and is - essentially a slight variation on the export-key.py script. - """) - - c = gpg.Context(armor=True) - server = hkp4py.KeyServer("hkps://hkps.pool.sks-keyservers.net") - - if len(sys.argv) > 2: - logrus = " ".join(sys.argv[1:]) - elif len(sys.argv) == 2: - logrus = sys.argv[1] - else: - logrus = input("Enter the UID matching the key(s) to send: ") - - if len(logrus) > 0: - try: - export_result = c.key_export(pattern=logrus) - except Exception as e: - print(e) - export_result = None - else: - export_result = c.key_export(pattern=None) - - if export_result is not None: - try: - try: - send_result = server.add(export_result) - except: - send_result = server.add(export_result.decode()) - if send_result is not None: - print(send_result) - else: - pass - except Exception as e: - print(e) - else: - pass - -An expanded version of this script with additional functions for -specifying an alternative homedir location is in the examples directory -as ``send-key-to-keyserver.py``. - -The ``hkp4py`` module appears to handle both string and byte literal -text data equally well, but the GPGME bindings deal primarily with byte -literal data only and so this script sends in that format first, then -tries the string literal form. - -.. _howto-the-basics: - -Basic Functions -=============== - -The most frequently called features of any cryptographic library will be -the most fundamental tasks for encryption software. In this section we -will look at how to programmatically encrypt data, decrypt it, sign it -and verify signatures. - -.. _howto-basic-encryption: - -Encryption ----------- - -Encrypting is very straight forward. In the first example below the -message, ``text``, is encrypted to a single recipient\'s key. In the -second example the message will be encrypted to multiple recipients. - -.. _howto-basic-encryption-single: - -Encrypting to one key -~~~~~~~~~~~~~~~~~~~~~ - -Once the the Context is set the main issues with encrypting data is -essentially reduced to key selection and the keyword arguments specified -in the ``gpg.Context().encrypt()`` method. - -Those keyword arguments are: ``recipients``, a list of keys encrypted to -(covered in greater detail in the following section); ``sign``, whether -or not to sign the plaintext data, see subsequent sections on signing -and verifying signatures below (defaults to ``True``); ``sink``, to -write results or partial results to a secure sink instead of returning -it (defaults to ``None``); ``passphrase``, only used when utilising -symmetric encryption (defaults to ``None``); ``always_trust``, used to -override the trust model settings for recipient keys (defaults to -``False``); ``add_encrypt_to``, utilises any preconfigured -``encrypt-to`` or ``default-key`` settings in the user\'s ``gpg.conf`` -file (defaults to ``False``); ``prepare``, prepare for encryption -(defaults to ``False``); ``expect_sign``, prepare for signing (defaults -to ``False``); ``compress``, compresses the plaintext prior to -encryption (defaults to ``True``). - -.. code:: python - - import gpg - - a_key = "0x12345678DEADBEEF" - text = b"""Some text to test with. - - Since the text in this case must be bytes, it is most likely that - the input form will be a separate file which is opened with "rb" - as this is the simplest method of obtaining the correct data format. - """ - - c = gpg.Context(armor=True) - rkey = list(c.keylist(pattern=a_key, secret=False)) - ciphertext, result, sign_result = c.encrypt(text, recipients=rkey, sign=False) - - with open("secret_plans.txt.asc", "wb") as afile: - afile.write(ciphertext) - -Though this is even more likely to be used like this; with the plaintext -input read from a file, the recipient keys used for encryption -regardless of key trust status and the encrypted output also encrypted -to any preconfigured keys set in the ``gpg.conf`` file: - -.. code:: python - - import gpg - - a_key = "0x12345678DEADBEEF" - - with open("secret_plans.txt", "rb") as afile: - text = afile.read() - - c = gpg.Context(armor=True) - rkey = list(c.keylist(pattern=a_key, secret=False)) - ciphertext, result, sign_result = c.encrypt(text, recipients=rkey, sign=True, - always_trust=True, - add_encrypt_to=True) - - with open("secret_plans.txt.asc", "wb") as afile: - afile.write(ciphertext) - -If the ``recipients`` parameter is empty then the plaintext is encrypted -symmetrically. If no ``passphrase`` is supplied as a parameter or via a -callback registered with the ``Context()`` then an out-of-band prompt -for the passphrase via pinentry will be invoked. - -.. _howto-basic-encryption-multiple: - -Encrypting to multiple keys -~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -Encrypting to multiple keys essentially just expands upon the key -selection process and the recipients from the previous examples. - -The following example encrypts a message (``text``) to everyone with an -email address on the ``gnupg.org`` domain, [4]_ but does *not* encrypt -to a default key or other key which is configured to normally encrypt -to. - -.. code:: python - - import gpg - - text = b"""Oh look, another test message. - - The same rules apply as with the previous example and more likely - than not, the message will actually be drawn from reading the - contents of a file or, maybe, from entering data at an input() - prompt. - - Since the text in this case must be bytes, it is most likely that - the input form will be a separate file which is opened with "rb" - as this is the simplest method of obtaining the correct data - format. - """ - - c = gpg.Context(armor=True) - rpattern = list(c.keylist(pattern="@gnupg.org", secret=False)) - logrus = [] - - for i in range(len(rpattern)): - if rpattern[i].can_encrypt == 1: - logrus.append(rpattern[i]) - - ciphertext, result, sign_result = c.encrypt(text, recipients=logrus, - sign=False, always_trust=True) - - with open("secret_plans.txt.asc", "wb") as afile: - afile.write(ciphertext) - -All it would take to change the above example to sign the message and -also encrypt the message to any configured default keys would be to -change the ``c.encrypt`` line to this: - -.. code:: python - - ciphertext, result, sign_result = c.encrypt(text, recipients=logrus, - always_trust=True, - add_encrypt_to=True) - -The only keyword arguments requiring modification are those for which -the default values are changing. The default value of ``sign`` is -``True``, the default of ``always_trust`` is ``False``, the default of -``add_encrypt_to`` is ``False``. - -If ``always_trust`` is not set to ``True`` and any of the recipient keys -are not trusted (e.g. not signed or locally signed) then the encryption -will raise an error. It is possible to mitigate this somewhat with -something more like this: - -.. code:: python - - import gpg - - with open("secret_plans.txt.asc", "rb") as afile: - text = afile.read() - - c = gpg.Context(armor=True) - rpattern = list(c.keylist(pattern="@gnupg.org", secret=False)) - logrus = [] - - for i in range(len(rpattern)): - if rpattern[i].can_encrypt == 1: - logrus.append(rpattern[i]) - - try: - ciphertext, result, sign_result = c.encrypt(text, recipients=logrus, - add_encrypt_to=True) - except gpg.errors.InvalidRecipients as e: - for i in range(len(e.recipients)): - for n in range(len(logrus)): - if logrus[n].fpr == e.recipients[i].fpr: - logrus.remove(logrus[n]) - else: - pass - try: - ciphertext, result, sign_result = c.encrypt(text, - recipients=logrus, - add_encrypt_to=True) - with open("secret_plans.txt.asc", "wb") as afile: - afile.write(ciphertext) - except: - pass - -This will attempt to encrypt to all the keys searched for, then remove -invalid recipients if it fails and try again. - -.. _howto-basic-decryption: - -Decryption ----------- - -Decrypting something encrypted to a key in one\'s secret keyring is -fairly straight forward. - -In this example code, however, preconfiguring either ``gpg.Context()`` -or ``gpg.core.Context()`` as ``c`` is unnecessary because there is no -need to modify the Context prior to conducting the decryption and since -the Context is only used once, setting it to ``c`` simply adds lines for -no gain. - -.. code:: python - - import gpg - - ciphertext = input("Enter path and filename of encrypted file: ") - newfile = input("Enter path and filename of file to save decrypted data to: ") - - with open(ciphertext, "rb") as cfile: - try: - plaintext, result, verify_result = gpg.Context().decrypt(cfile) - except gpg.errors.GPGMEError as e: - plaintext = None - print(e) - - if plaintext is not None: - with open(newfile, "wb") as nfile: - nfile.write(plaintext) - else: - pass - -The data available in ``plaintext`` in this example is the decrypted -content as a byte object, the recipient key IDs and algorithms in -``result`` and the results of verifying any signatures of the data in -``verify_result``. - -If ``gpg.Context().decrypt(cfile, verify=False)`` is called instead, -then ``verify_result`` will be returned as ``None`` and the rest remains -as described here. - -.. _howto-basic-signing: - -Signing text and files ----------------------- - -The following sections demonstrate how to specify keys to sign with. - -.. _howto-basic-signing-signers: - -Signing key selection -~~~~~~~~~~~~~~~~~~~~~ - -By default GPGME and the Python bindings will use the default key -configured for the user invoking the GPGME API. If there is no default -key specified and there is more than one secret key available it may be -necessary to specify the key or keys with which to sign messages and -files. - -.. code:: python - - import gpg - - logrus = input("Enter the email address or string to match signing keys to: ") - hancock = gpg.Context().keylist(pattern=logrus, secret=True) - sig_src = list(hancock) - -The signing examples in the following sections include the explicitly -designated ``signers`` parameter in two of the five examples; once where -the resulting signature would be ASCII armoured and once where it would -not be armoured. - -While it would be possible to enter a key ID or fingerprint here to -match a specific key, it is not possible to enter two fingerprints and -match two keys since the patten expects a string, bytes or None and not -a list. A string with two fingerprints won\'t match any single key. - -.. _howto-basic-signing-normal: - -Normal or default signing messages or files -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -The normal or default signing process is essentially the same as is most -often invoked when also encrypting a message or file. So when the -encryption component is not utilised, the result is to produce an -encoded and signed output which may or may not be ASCII armoured and -which may or may not also be compressed. - -By default compression will be used unless GnuPG detects that the -plaintext is already compressed. ASCII armouring will be determined -according to the value of ``gpg.Context().armor``. - -The compression algorithm is selected in much the same way as the -symmetric encryption algorithm or the hash digest algorithm is when -multiple keys are involved; from the preferences saved into the key -itself or by comparison with the preferences with all other keys -involved. - -.. code:: python - - import gpg - - text0 = """Declaration of ... something. - - """ - text = text0.encode() - - c = gpg.Context(armor=True, signers=sig_src) - signed_data, result = c.sign(text, mode=gpg.constants.sig.mode.NORMAL) - - with open("/path/to/statement.txt.asc", "w") as afile: - afile.write(signed_data.decode()) - -Though everything in this example is accurate, it is more likely that -reading the input data from another file and writing the result to a new -file will be performed more like the way it is done in the next example. -Even if the output format is ASCII armoured. - -.. code:: python - - import gpg - - with open("/path/to/statement.txt", "rb") as tfile: - text = tfile.read() - - c = gpg.Context() - signed_data, result = c.sign(text, mode=gpg.constants.sig.mode.NORMAL) - - with open("/path/to/statement.txt.sig", "wb") as afile: - afile.write(signed_data) - -.. _howto-basic-signing-detached: - -Detached signing messages and files -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -Detached signatures will often be needed in programmatic uses of GPGME, -either for signing files (e.g. tarballs of code releases) or as a -component of message signing (e.g. PGP/MIME encoded email). - -.. code:: python - - import gpg - - text0 = """Declaration of ... something. - - """ - text = text0.encode() - - c = gpg.Context(armor=True) - signed_data, result = c.sign(text, mode=gpg.constants.sig.mode.DETACH) - - with open("/path/to/statement.txt.asc", "w") as afile: - afile.write(signed_data.decode()) - -As with normal signatures, detached signatures are best handled as byte -literals, even when the output is ASCII armoured. - -.. code:: python - - import gpg - - with open("/path/to/statement.txt", "rb") as tfile: - text = tfile.read() - - c = gpg.Context(signers=sig_src) - signed_data, result = c.sign(text, mode=gpg.constants.sig.mode.DETACH) - - with open("/path/to/statement.txt.sig", "wb") as afile: - afile.write(signed_data) - -.. _howto-basic-signing-clear: - -Clearsigning messages or text -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -Though PGP/in-line messages are no longer encouraged in favour of -PGP/MIME, there is still sometimes value in utilising in-line -signatures. This is where clear-signed messages or text is of value. - -.. code:: python - - import gpg - - text0 = """Declaration of ... something. - - """ - text = text0.encode() - - c = gpg.Context() - signed_data, result = c.sign(text, mode=gpg.constants.sig.mode.CLEAR) - - with open("/path/to/statement.txt.asc", "w") as afile: - afile.write(signed_data.decode()) - -In spite of the appearance of a clear-signed message, the data handled -by GPGME in signing it must still be byte literals. - -.. code:: python - - import gpg - - with open("/path/to/statement.txt", "rb") as tfile: - text = tfile.read() - - c = gpg.Context() - signed_data, result = c.sign(text, mode=gpg.constants.sig.mode.CLEAR) - - with open("/path/to/statement.txt.asc", "wb") as afile: - afile.write(signed_data) - -.. _howto-basic-verification: - -Signature verification ----------------------- - -Essentially there are two principal methods of verification of a -signature. The first of these is for use with the normal or default -signing method and for clear-signed messages. The second is for use with -files and data with detached signatures. - -The following example is intended for use with the default signing -method where the file was not ASCII armoured: - -.. code:: python - - import gpg - import time - - filename = "statement.txt" - gpg_file = "statement.txt.gpg" - - c = gpg.Context() - - try: - data, result = c.verify(open(gpg_file)) - verified = True - except gpg.errors.BadSignatures as e: - verified = False - print(e) - - if verified is True: - for i in range(len(result.signatures)): - sign = result.signatures[i] - print("""Good signature from: - {0} - with key {1} - made at {2} - """.format(c.get_key(sign.fpr).uids[0].uid, sign.fpr, - time.ctime(sign.timestamp))) - else: - pass - -Whereas this next example, which is almost identical would work with -normal ASCII armoured files and with clear-signed files: - -.. code:: python - - import gpg - import time - - filename = "statement.txt" - asc_file = "statement.txt.asc" - - c = gpg.Context() - - try: - data, result = c.verify(open(asc_file)) - verified = True - except gpg.errors.BadSignatures as e: - verified = False - print(e) - - if verified is True: - for i in range(len(result.signatures)): - sign = result.signatures[i] - print("""Good signature from: - {0} - with key {1} - made at {2} - """.format(c.get_key(sign.fpr).uids[0].uid, sign.fpr, - time.ctime(sign.timestamp))) - else: - pass - -In both of the previous examples it is also possible to compare the -original data that was signed against the signed data in ``data`` to see -if it matches with something like this: - -.. code:: python - - with open(filename, "rb") as afile: - text = afile.read() - - if text == data: - print("Good signature.") - else: - pass - -The following two examples, however, deal with detached signatures. With -his method of verification the data that was signed does not get -returned since it is already being explicitly referenced in the first -argument of ``c.verify``. So ``data`` is ``None`` and only the -information in ``result`` is available. - -.. code:: python - - import gpg - import time - - filename = "statement.txt" - sig_file = "statement.txt.sig" - - c = gpg.Context() - - try: - data, result = c.verify(open(filename), open(sig_file)) - verified = True - except gpg.errors.BadSignatures as e: - verified = False - print(e) - - if verified is True: - for i in range(len(result.signatures)): - sign = result.signatures[i] - print("""Good signature from: - {0} - with key {1} - made at {2} - """.format(c.get_key(sign.fpr).uids[0].uid, sign.fpr, - time.ctime(sign.timestamp))) - else: - pass - -.. code:: python - - import gpg - import time - - filename = "statement.txt" - asc_file = "statement.txt.asc" - - c = gpg.Context() - - try: - data, result = c.verify(open(filename), open(asc_file)) - verified = True - except gpg.errors.BadSignatures as e: - verified = False - print(e) - - if verified is True: - for i in range(len(result.signatures)): - sign = result.signatures[i] - print("""Good signature from: - {0} - with key {1} - made at {2} - """.format(c.get_key(sign.fpr).uids[0].uid, sign.fpr, - time.ctime(sign.timestamp))) - else: - pass - -.. _key-generation: - -Creating keys and subkeys -========================= - -The one thing, aside from GnuPG itself, that GPGME depends on, of -course, is the keys themselves. So it is necessary to be able to -generate them and modify them by adding subkeys, revoking or disabling -them, sometimes deleting them and doing the same for user IDs. - -In the following examples a key will be created for the world\'s -greatest secret agent, Danger Mouse. Since Danger Mouse is a secret -agent he needs to be able to protect information to ``SECRET`` level -clearance, so his keys will be 3072-bit keys. - -The pre-configured ``gpg.conf`` file which sets cipher, digest and other -preferences contains the following configuration parameters: - -.. code:: conf - - expert - allow-freeform-uid - allow-secret-key-import - trust-model tofu+pgp - tofu-default-policy unknown - enable-large-rsa - enable-dsa2 - cert-digest-algo SHA512 - default-preference-list TWOFISH CAMELLIA256 AES256 CAMELLIA192 AES192 CAMELLIA128 AES BLOWFISH IDEA CAST5 3DES SHA512 SHA384 SHA256 SHA224 RIPEMD160 SHA1 ZLIB BZIP2 ZIP Uncompressed - personal-cipher-preferences TWOFISH CAMELLIA256 AES256 CAMELLIA192 AES192 CAMELLIA128 AES BLOWFISH IDEA CAST5 3DES - personal-digest-preferences SHA512 SHA384 SHA256 SHA224 RIPEMD160 SHA1 - personal-compress-preferences ZLIB BZIP2 ZIP Uncompressed - -.. _keygen-primary: - -Primary key ------------ - -Generating a primary key uses the ``create_key`` method in a Context. It -contains multiple arguments and keyword arguments, including: -``userid``, ``algorithm``, ``expires_in``, ``expires``, ``sign``, -``encrypt``, ``certify``, ``authenticate``, ``passphrase`` and -``force``. The defaults for all of those except ``userid``, -``algorithm``, ``expires_in``, ``expires`` and ``passphrase`` is -``False``. The defaults for ``algorithm`` and ``passphrase`` is -``None``. The default for ``expires_in`` is ``0``. The default for -``expires`` is ``True``. There is no default for ``userid``. - -If ``passphrase`` is left as ``None`` then the key will not be generated -with a passphrase, if ``passphrase`` is set to a string then that will -be the passphrase and if ``passphrase`` is set to ``True`` then -gpg-agent will launch pinentry to prompt for a passphrase. For the sake -of convenience, these examples will keep ``passphrase`` set to ``None``. - -.. code:: python - - import gpg - - c = gpg.Context() - - c.home_dir = "~/.gnupg-dm" - userid = "Danger Mouse <[email protected]>" - - dmkey = c.create_key(userid, algorithm="rsa3072", expires_in=31536000, - sign=True, certify=True) - -One thing to note here is the use of setting the ``c.home_dir`` -parameter. This enables generating the key or keys in a different -location. In this case to keep the new key data created for this example -in a separate location rather than adding it to existing and active key -store data. As with the default directory, ``~/.gnupg``, any temporary -or separate directory needs the permissions set to only permit access by -the directory owner. On posix systems this means setting the directory -permissions to 700. - -The ``temp-homedir-config.py`` script in the HOWTO examples directory -will create an alternative homedir with these configuration options -already set and the correct directory and file permissions. - -The successful generation of the key can be confirmed via the returned -``GenkeyResult`` object, which includes the following data: - -.. code:: python - - print(""" - Fingerprint: {0} - Primary Key: {1} - Public Key: {2} - Secret Key: {3} - Sub Key: {4} - User IDs: {5} - """.format(dmkey.fpr, dmkey.primary, dmkey.pubkey, dmkey.seckey, dmkey.sub, - dmkey.uid)) - -Alternatively the information can be confirmed using the command line -program: - -.. code:: shell - - bash-4.4$ gpg --homedir ~/.gnupg-dm -K - ~/.gnupg-dm/pubring.kbx - ---------------------- - sec rsa3072 2018-03-15 [SC] [expires: 2019-03-15] - 177B7C25DB99745EE2EE13ED026D2F19E99E63AA - uid [ultimate] Danger Mouse <[email protected]> - - bash-4.4$ - -As with generating keys manually, to preconfigure expanded preferences -for the cipher, digest and compression algorithms, the ``gpg.conf`` file -must contain those details in the home directory in which the new key is -being generated. I used a cut down version of my own ``gpg.conf`` file -in order to be able to generate this: - -.. code:: shell - - bash-4.4$ gpg --homedir ~/.gnupg-dm --edit-key 177B7C25DB99745EE2EE13ED026D2F19E99E63AA showpref quit - Secret key is available. - - sec rsa3072/026D2F19E99E63AA - created: 2018-03-15 expires: 2019-03-15 usage: SC - trust: ultimate validity: ultimate - [ultimate] (1). Danger Mouse <[email protected]> - - [ultimate] (1). Danger Mouse <[email protected]> - Cipher: TWOFISH, CAMELLIA256, AES256, CAMELLIA192, AES192, CAMELLIA128, AES, BLOWFISH, IDEA, CAST5, 3DES - Digest: SHA512, SHA384, SHA256, SHA224, RIPEMD160, SHA1 - Compression: ZLIB, BZIP2, ZIP, Uncompressed - Features: MDC, Keyserver no-modify - - bash-4.4$ - -.. _keygen-subkeys: - -Subkeys -------- - -Adding subkeys to a primary key is fairly similar to creating the -primary key with the ``create_subkey`` method. Most of the arguments are -the same, but not quite all. Instead of the ``userid`` argument there is -now a ``key`` argument for selecting which primary key to add the subkey -to. - -In the following example an encryption subkey will be added to the -primary key. Since Danger Mouse is a security conscious secret agent, -this subkey will only be valid for about six months, half the length of -the primary key. - -.. code:: python - - import gpg - - c = gpg.Context() - c.home_dir = "~/.gnupg-dm" - - key = c.get_key(dmkey.fpr, secret=True) - dmsub = c.create_subkey(key, algorithm="rsa3072", expires_in=15768000, - encrypt=True) - -As with the primary key, the results here can be checked with: - -.. code:: python - - print(""" - Fingerprint: {0} - Primary Key: {1} - Public Key: {2} - Secret Key: {3} - Sub Key: {4} - User IDs: {5} - """.format(dmsub.fpr, dmsub.primary, dmsub.pubkey, dmsub.seckey, dmsub.sub, - dmsub.uid)) - -As well as on the command line with: - -.. code:: shell - - bash-4.4$ gpg --homedir ~/.gnupg-dm -K - ~/.gnupg-dm/pubring.kbx - ---------------------- - sec rsa3072 2018-03-15 [SC] [expires: 2019-03-15] - 177B7C25DB99745EE2EE13ED026D2F19E99E63AA - uid [ultimate] Danger Mouse <[email protected]> - ssb rsa3072 2018-03-15 [E] [expires: 2018-09-13] - - bash-4.4$ - -.. _keygen-uids: - -User IDs --------- - -.. _keygen-uids-add: - -Adding User IDs -~~~~~~~~~~~~~~~ - -By comparison to creating primary keys and subkeys, adding a new user ID -to an existing key is much simpler. The method used to do this is -``key_add_uid`` and the only arguments it takes are for the ``key`` and -the new ``uid``. - -.. code:: python - - import gpg - - c = gpg.Context() - c.home_dir = "~/.gnupg-dm" - - dmfpr = "177B7C25DB99745EE2EE13ED026D2F19E99E63AA" - key = c.get_key(dmfpr, secret=True) - uid = "Danger Mouse <[email protected]>" - - c.key_add_uid(key, uid) - -Unsurprisingly the result of this is: - -.. code:: shell - - bash-4.4$ gpg --homedir ~/.gnupg-dm -K - ~/.gnupg-dm/pubring.kbx - ---------------------- - sec rsa3072 2018-03-15 [SC] [expires: 2019-03-15] - 177B7C25DB99745EE2EE13ED026D2F19E99E63AA - uid [ultimate] Danger Mouse <[email protected]> - uid [ultimate] Danger Mouse <[email protected]> - ssb rsa3072 2018-03-15 [E] [expires: 2018-09-13] - - bash-4.4$ - -.. _keygen-uids-revoke: - -Revoking User IDs -~~~~~~~~~~~~~~~~~ - -Revoking a user ID is a fairly similar process, except that it uses the -``key_revoke_uid`` method. - -.. code:: python - - import gpg - - c = gpg.Context() - c.home_dir = "~/.gnupg-dm" - - dmfpr = "177B7C25DB99745EE2EE13ED026D2F19E99E63AA" - key = c.get_key(dmfpr, secret=True) - uid = "Danger Mouse <[email protected]>" - - c.key_revoke_uid(key, uid) - -.. _key-sign: - -Key certification ------------------ - -Since key certification is more frequently referred to as key signing, -the method used to perform this function is ``key_sign``. - -The ``key_sign`` method takes four arguments: ``key``, ``uids``, -``expires_in`` and ``local``. The default value of ``uids`` is ``None`` -and which results in all user IDs being selected. The default value of -both ``expires_in`` and ``local`` is ``False``; which results in the -signature never expiring and being able to be exported. - -The ``key`` is the key being signed rather than the key doing the -signing. To change the key doing the signing refer to the signing key -selection above for signing messages and files. - -If the ``uids`` value is not ``None`` then it must either be a string to -match a single user ID or a list of strings to match multiple user IDs. -In this case the matching of those strings must be precise and it is -case sensitive. - -To sign Danger Mouse\'s key for just the initial user ID with a -signature which will last a little over a month, do this: - -.. code:: python - - import gpg - - c = gpg.Context() - uid = "Danger Mouse <[email protected]>" - - dmfpr = "177B7C25DB99745EE2EE13ED026D2F19E99E63AA" - key = c.get_key(dmfpr, secret=True) - c.key_sign(key, uids=uid, expires_in=2764800) - -.. _key-sign-verify: - -Verifying key certifications -~~~~~~~~~~~~~~~~~~~~~~~~~~~~ - -.. code:: python - - import gpg - import time - - c = gpg.Context() - dmfpr = "177B7C25DB99745EE2EE13ED026D2F19E99E63AA" - keys = list(c.keylist(pattern=dmuid, mode=gpg.constants.keylist.mode.SIGS)) - key = keys[0] - - for user in key.uids: - for sig in user.signatures: - print("0x{0}".format(sig.keyid), "", time.ctime(sig.timestamp), "", - sig.uid) - -Which for Danger Mouse displays the following: - -:: - - 0x92E3F6115435C65A Thu Mar 15 13:17:44 2018 Danger Mouse <[email protected]> - 0x321E4E2373590E5D Mon Nov 26 12:46:05 2018 Ben McGinnes <[email protected]> - -The two key signatures listed are for the self-certification of Danger -Mouse\'s key made when the key was created in March, 2018; and the -second is a signature made by the author and set to expire at the end of -the year. Note that the second signature was made with the following -code (including the preceding code to display the output of the -certifications or key signatures): - -.. code:: python - - import gpg - import math - import pendulum - import time - - hd = "/home/dm/.gnupg" - c = gpg.Context() - d = gpg.Context(home_dir=hd) - dmfpr = "177B7C25DB99745EE2EE13ED026D2F19E99E63AA" - dmuid = "Danger Mouse <[email protected]>" - dkeys = list(c.keylist(pattern=dmuid)) - dmkey = dkeys[0] - - c.key_import(d.key_export(pattern=None)) - - tp = pendulum.period(pendulum.now(tz="local"), pendulum.datetime(2019, 1, 1)) - ts = tp.total_seconds() - total_secs = math.ceil(ts) - c.key_sign(dmkey, uids=dmuid, expires_in=total_secs) - - d.key_import(c.key_export(pattern=dmuid)) - keys = list(c.keylist(pattern=dmuid, mode=gpg.constants.keylist.mode.SIGS)) - key = keys[0] - - for user in key.uids: - for sig in user.signatures: - print("0x{0}".format(sig.keyid), "", time.ctime(sig.timestamp), "", - sig.uid) - -Note that this final code block includes the use of a module which is -*not* part of Python\'s standard library, the `pendulum -module <https://pendulum.eustace.io/>`__. Unlike the standard datetime -module, pendulum makes working with dates and times significantly easier -in Python; just as the requests module makes working with HTTP and HTTPS -easier than the builtin modules do. - -Though neither requests nor pendulum are required modules for using the -GPGME Python bindings, they are both highly recommended more generally. - -.. _advanced-use: - -Advanced or Experimental Use Cases -================================== - -.. _cython: - -C plus Python plus SWIG plus Cython ------------------------------------ - -In spite of the apparent incongruence of using Python bindings to a C -interface only to generate more C from the Python; it is in fact quite -possible to use the GPGME bindings with -`Cython <http://docs.cython.org/en/latest/index.html>`__. Though in many -cases the benefits may not be obvious since the most computationally -intensive work never leaves the level of the C code with which GPGME -itself is interacting with. - -Nevertheless, there are some situations where the benefits are -demonstrable. One of the better and easier examples being the one of the -early examples in this HOWTO, the `key -counting <#howto-keys-counting>`__ code. Running that example as an -executable Python script, ``keycount.py`` (available in the -``examples/howto/`` directory), will take a noticeable amount of time to -run on most systems where the public keybox or keyring contains a few -thousand public keys. - -Earlier in the evening, prior to starting this section, I ran that -script on my laptop; as I tend to do periodically and timed it using -``time`` utility, with the following results: - -.. code:: shell - - bash-4.4$ time keycount.py - - Number of secret keys: 23 - Number of public keys: 12112 - - - real 11m52.945s - user 0m0.913s - sys 0m0.752s - - bash-4.4$ - -Sometime after that I imported another key and followed it with a little -test of Cython. This test was kept fairly basic, essentially lifting the -material from the `Cython Basic -Tutorial <http://docs.cython.org/en/latest/src/tutorial/cython_tutorial.html>`__ -to demonstrate compiling Python code to C. The first step was to take -the example key counting code quoted previously, essentially from the -importing of the ``gpg`` module to the end of the script: - -.. code:: python - - import gpg - - c = gpg.Context() - seckeys = c.keylist(pattern=None, secret=True) - pubkeys = c.keylist(pattern=None, secret=False) - - seclist = list(seckeys) - secnum = len(seclist) - - publist = list(pubkeys) - pubnum = len(publist) - - print(""" - Number of secret keys: {0} - Number of public keys: {1} - - """.format(secnum, pubnum)) - -Save that into a file called ``keycount.pyx`` and then create a -``setup.py`` file which contains this: - -.. code:: python - - from distutils.core import setup - from Cython.Build import cythonize - - setup( - ext_modules = cythonize("keycount.pyx") - ) - -Compile it: - -.. code:: shell - - bash-4.4$ python setup.py build_ext --inplace - bash-4.4$ - -Then run it in a similar manner to ``keycount.py``: - -.. code:: shell - - bash-4.4$ time python3.7 -c "import keycount" - - Number of secret keys: 23 - Number of public keys: 12113 - - - real 6m47.905s - user 0m0.785s - sys 0m0.331s - - bash-4.4$ - -Cython turned ``keycount.pyx`` into an 81KB ``keycount.o`` file in the -``build/`` directory, a 24KB ``keycount.cpython-37m-darwin.so`` file to -be imported into Python 3.7 and a 113KB ``keycount.c`` generated C -source code file of nearly three thousand lines. Quite a bit bigger than -the 314 bytes of the ``keycount.pyx`` file or the full 1,452 bytes of -the full executable ``keycount.py`` example script. - -On the other hand it ran in nearly half the time; taking 6 minutes and -47.905 seconds to run. As opposed to the 11 minutes and 52.945 seconds -which the CPython script alone took. - -The ``keycount.pyx`` and ``setup.py`` files used to generate this -example have been added to the ``examples/howto/advanced/cython/`` -directory The example versions include some additional options to -annotate the existing code and to detect Cython\'s use. The latter comes -from the `Magic -Attributes <http://docs.cython.org/en/latest/src/tutorial/pure.html#magic-attributes-within-the-pxd>`__ -section of the Cython documentation. - -.. _cheats-and-hacks: - -Miscellaneous extras and work-arounds -===================================== - -Most of the things in the following sections are here simply because -there was no better place to put them, even though some are only -peripherally related to the GPGME Python bindings. Some are also -workarounds for functions not integrated with GPGME as yet. This is -especially true of the first of these, dealing with `group -lines <#group-lines>`__. - -Group lines ------------ - -There is not yet an easy way to access groups configured in the gpg.conf -file from within GPGME. As a consequence these central groupings of keys -cannot be shared amongst multiple programs, such as MUAs readily. - -The following code, however, provides a work-around for obtaining this -information in Python. - -.. code:: python - - import subprocess - import sys - - if sys.platform == "win32": - gpgconfcmd = "gpgconf.exe --list-options gpg" - else: - gpgconfcmd = "gpgconf --list-options gpg" - - process = subprocess.Popen(gpgconfcmd.split(), stdout=subprocess.PIPE) - procom = process.communicate() - - if sys.version_info[0] == 2: - lines = procom[0].splitlines() - else: - lines = procom[0].decode().splitlines() - - for line in lines: - if line.startswith("group") is True: - break - - groups = line.split(":")[-1].replace('"', '').split(',') - - group_lines = [] - group_lists = [] - - for group in groups: - group_lines.append(group.split("=")) - group_lists.append(group.split("=")) - - for glist in group_lists: - glist[1] = glist[1].split() - -The result of that code is that ``group_lines`` is a list of lists where -``group_lines[i][0]`` is the name of the group and ``group_lines[i][1]`` -is the key IDs of the group as a string. - -The ``group_lists`` result is very similar in that it is a list of -lists. The first part, ``group_lists[i][0]`` matches -``group_lines[i][0]`` as the name of the group, but -``group_lists[i][1]`` is the key IDs of the group as a list. - -A demonstration of using the ``groups.py`` module is also available in -the form of the executable ``mutt-groups.py`` script. This second script -reads all the group entries in a user\'s ``gpg.conf`` file and converts -them into crypt-hooks suitable for use with the Mutt and Neomutt mail -clients. - -.. _hkp4py: - -Keyserver access for Python ---------------------------- - -The `hkp4py <https://github.com/Selfnet/hkp4py>`__ module by Marcel Fest -was originally a port of the old -`python-hkp <https://github.com/dgladkov/python-hkp>`__ module from -Python 2 to Python 3 and updated to use the -`requests <http://docs.python-requests.org/en/latest/index.html>`__ -module instead. It has since been modified to provide support for Python -2.7 as well and is available via PyPI. - -Since it rewrites the ``hkp`` protocol prefix as ``http`` and ``hkps`` -as ``https``, the module is able to be used even with servers which do -not support the full scope of keyserver functions. [5]_ It also works -quite readily when incorporated into a `Cython <#cython>`__ generated -and compiled version of any code. - -.. _hkp4py-strings: - -Key import format -~~~~~~~~~~~~~~~~~ - -The hkp4py module returns key data via requests as string literals -(``r.text``) instead of byte literals (``r.content``). This means that -the retrurned key data must be encoded to UTF-8 when importing that key -material using a ``gpg.Context().key_import()`` method. - -For this reason an alternative method has been added to the ``search`` -function of ``hkp4py.KeyServer()`` which returns the key in the correct -format as expected by ``key_import``. When importing using this module, -it is now possible to import with this: - -.. code:: python - - for key in keys: - if key.revoked is False: - gpg.Context().key_import(key.key_blob) - else: - pass - -Without that recent addition it would have been necessary to encode the -contents of each ``hkp4py.KeyServer().search()[i].key`` in -``hkp4py.KeyServer().search()`` before trying to import it. - -An example of this is included in the `Importing -Keys <#howto-import-key>`__ section of this HOWTO and the corresponding -executable version of that example is available in the -``lang/python/examples/howto`` directory as normal; the executable -version is the ``import-keys-hkp.py`` file. - -.. _gpgme-version-check: - -GPGME version checking ----------------------- - -For various reasons it may be necessary to check which version of GPGME -the bindings have been built against; including whether a minimum -required version of GPGME is in use. - -For the most part the ``gpg.version.versionstr`` and -``gpg.version.versionlist`` methods have been quite sufficient. The -former returns the same string as ``gpgme-config --version``, while the -latter returns the major, minor and patch values in a list. - -To check if the installed bindings have actually been built against the -current installed libgpgme version, this check can be performed: - -.. code:: python - - import gpg - import subprocess - import sys - - gpgme_version_call = subprocess.Popen(["gpgme-config", "--version"], - stdout=subprocess.PIPE, - stderr=subprocess.PIPE) - gpgme_version_str = gpgme_version_call.communicate() - - if sys.version_info[0] == 2: - gpgme_version = gpgme_version_str[0].strip() - elif sys.version_info[0] >= 3: - gpgme_version = gpgme_version_str[0].decode().strip() - else: - gpgme_version = None - - if gpgme_version is not None: - if gpgme_version == gpg.version.versionstr: - print("The GPGME Python bindings match libgpgme.") - else: - print("The GPGME Python bindings do NOT match libgpgme.") - else: - print("Upgrade Python and reinstall the GPGME Python bindings.") - -For many developers, however, the preferred checking means checking for -a minimum version or point release. This is now readily available via -the ``gpg.version.versionintlist`` method (added in version -``1.12.1-beta79``). It is also now possible to easily check whether the -installed GPGME Python bindings were built from a development or beta -branch of the GPGME source code. - -The following code demonstrates how both of those methods may be used: - -.. code:: python - - import gpg - - try: - if gpg.version.is_beta is True: - print("The installed GPGME Python bindings were built from beta code.") - else: - print("The installed GPGME Python bindings are a released version.") - except Exception as e: - print(e) - - try: - if gpg.version.versionintlist[0] == 1: - if gpg.version.versionintlist[1] == 12: - if gpg.version.versionintlist[2] == 1: - print("This is the minimum version for using versionintlist.") - elif gpg.version.versionintlist[2] > 1: - print("The versionintlist method is available.") - else: - pass - elif gpg.version.versionintlist[1] > 12: - print("The versionintlist method is available.") - else: - pass - elif gpg.version.versionintlist[0] > 1: - print("The versionintlist method is available.") - else: - pass - except Exception as e: - print(e) - -The points where ``pass`` is used in the above example will most likely -also produce an ``Exception`` error since those results should only -occur in versions which do not have the ``gpgme.version.is_beta`` and -``gpgme.version.versionintlist`` methods available. - -.. _copyright-and-license: - -Copyright and Licensing -======================= - -Copyright ---------- - -Copyright © The GnuPG Project, 2018. - -.. _draft-editions: - -Draft Editions of this HOWTO ----------------------------- - -Draft editions of this HOWTO may be periodically available directly from -the author at any of the following URLs: - -- `GPGME Python Bindings HOWTO draft (HTML single file, AWS S3 - SSL) <https://files.au.adversary.org/crypto/gpgme-python-howto.html>`__ -- `GPGME Python Bindings HOWTO draft (HTML single file, AWS S3 no - SSL) <http://files.au.adversary.org/crypto/gpgme-python-howto.html>`__ -- `GPGME Python Bindings HOWTO draft (HTML multiple files, AWS S3 - SSL) <https://files.au.adversary.org/crypto/gpgme-python-howto-split/index.html>`__ -- `GPGME Python Bindings HOWTO draft (HTML multiple files, AWS S3 no - SSL) <http://files.au.adversary.org/crypto/gpgme-python-howto/index.html>`__ - -These draft versions have been generated from this document via GNU -Emacs `Org mode <https://orgmode.org/>`__ to ``.texi`` and `GNU -Texinfo <https://www.gnu.org/software/texinfo/>`__ to HTML. Though it is -likely that the specific -`file <https://files.au.adversary.org/crypto/gpgme-python-howto>`__ -`version <http://files.au.adversary.org/crypto/gpgme-python-howto.org>`__ -used will be on the same server with the generated output formats. -Occasionally I may include the Org mode generated XHTML versions: - -- `GPGME Python Bindings HOWTO draft (HTML single file, AWS S3 - SSL) <https://files.au.adversary.org/crypto/gpgme-python-howto.xhtml>`__ -- `GPGME Python Bindings HOWTO draft (HTML single file, AWS S3 no - SSL) <http://files.au.adversary.org/crypto/gpgme-python-howto.xhtml>`__ - -That XHTML version, however, is exported in a way which inherits a -colour scheme from `the author\'s Emacs -theme <https://github.com/holomorph/emacs-zenburn>`__ (which is a higher -contrast version of `Zenburn <http://kippura.org/zenburnpage/>`__ ported -by `Holomorph <https://github.com/holomorph>`__). So it\'s fine for -people who prefer dark themed web pages, but not so great for everyone -else. - -The GNU Texinfo and reStructured Text versions ship with the software, -while the GNU Emacs Info version is generated from the Texinfo version -using GNU Texinfo or GNU Makeinfo. The Texinfo format is generated from -the original Org mode source file in Org mode itself either within GNU -Emacs or via the command line by invoking Emacs in batch mode: - -.. code:: shell - - emacs gpgme-python-howto.org --batch -f org-texinfo-export-to-texinfo --kill - emacs gpgme-python-howto --batch -f org-texinfo-export-to-texinfo --kill - -The reStructuredText format is also generated from the Org mode source -file, except it is generated using `Pandoc <https://pandoc.org>`__ with -either of the following commands (depending on the filename): - -.. code:: shell - - pandoc -f org -t rst+smart -o gpgme-python-howto.rst gpgme-python-howto.org - pandoc -f org -t rst+smart -o gpgme-python-howto.rst gpgme-python-howto - -Note that the Org mode source files are identified as such via a mode -line at the top of each file and have had their ``.org`` file extensions -dropped in order to make scripted generation of output formats easier -and not require renaming files post-conversion. - -Due to a bug in Org mode\'s texinfo conversion method, the recommended -steps for generating the Texinfo files for all the files in the -``lang/python/doc/src/`` directory are as follows: - -.. code:: shell - - for x in * ; do - emacs $x --batch -f org-texinfo-export-to-texinfo --kill - cat $x.texi | sed -e 's/@documentencoding UTF-8/@documentencoding utf-8/g' > ../texinfo/$x.texi - pandoc -f org -t rst+smart -o ../rst/$x.rst $x - done ; - rm -fv *.texi - cd ../texinfo - mkdir info - mkdir html - for x in *.texi ; do - makeinfo -v $x - makeinfo --html --no-split $x - done ; - mv *.info info/ - mv *.html html/ - -This code snippet includes the generation of the reStructuredText files -and would be expected to be run from the ``doc/src/`` directory -containing the Org mode source files. It also assumes that the commands -are being run on POSIX compliant systems with basic tools like sed, the -Bourne shell and GNU Emacs [6]_ available. The code snippet also -includes the steps for generating the Emacs Info files and HTML files -from the Texinfo files. Using reStructuredText files with Sphinx is best -left for the documentation of that project. - -In addition to these there is a significantly less frequently updated -version as a HTML `WebHelp -site <https://files.au.adversary.org/crypto/gpgme-python/dita/webhelp/index.html>`__ -(AWS S3 SSL); generated from DITA XML source files, which can be found -in `an alternative -branch <https://dev.gnupg.org/source/gpgme/browse/ben%252Fhowto-dita/>`__ -of the GPGME git repository. - -Various generated output formats may occasionally be found in -subdirectories of the -`gpgme-python <https://s3.amazonaws.com/files.au.adversary.org/crypto/gpgme-python>`__ -directory. In particular within the -`DITA <https://s3.amazonaws.com/files.au.adversary.org/crypto/gpgme-python/dita>`__, -`reStructuredText <https://s3.amazonaws.com/files.au.adversary.org/crypto/gpgme-python/rst>`__ -and -`Texinfo <https://s3.amazonaws.com/files.au.adversary.org/crypto/gpgme-python/texinfo>`__ -subdirectories. The ``rst`` directory contains output files generated -with Sphinx and may include a considerable number of its possible output -formats, but there are no guarantees as to how recent these are or even -if they are present. - -These draft editions are not official documents and the version of -documentation in the master branch or which ships with released versions -is the only official documentation. Nevertheless, these draft editions -may occasionally be of use by providing more accessible web versions -which are updated between releases. They are provided on the -understanding that they may contain errors or may contain content -subject to change prior to an official release. - -.. _license: - -License GPL compatible ----------------------- - -This file is free software; as a special exception the author gives -unlimited permission to copy and/or distribute it, with or without -modifications, as long as this notice is preserved. - -This file is distributed in the hope that it will be useful, but WITHOUT -ANY WARRANTY, to the extent permitted by law; without even the implied -warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. - -Footnotes -========= - -.. [1] - ``short-history`` and/or ``short-history.html``. - -.. [2] - With no issues reported specific to Python 3.7, the release of Python - 3.7.1 at around the same time as GPGME 1.12.0 and the testing with - Python 3.7.1rc1, there is no reason to delay moving 3.7 ahead of 3.6 - now. Production environments with more conservative requirements will - always enforce their own policies anyway and installation to each - supported minor release is quite possible too. - -.. [3] - Yes, even if you use virtualenv with everything you do in Python. If - you want to install this module as just your user account then you - will need to manually configure, compile and install the *entire* - GnuPG stack as that user as well. This includes libraries which are - not often installed that way. It can be done and there are - circumstances under which it is worthwhile, but generally only on - POSIX systems which utilise single user mode (some even require it). - -.. [4] - You probably don\'t really want to do this. Searching the keyservers - for \"gnupg.org\" produces over 400 results, the majority of which - aren\'t actually at the gnupg.org domain, but just included a comment - regarding the project in their key somewhere. - -.. [5] - Such as with ProtonMail servers. This also means that restricted - servers which only advertise either HTTP or HTTPS end points and not - HKP or HKPS end points must still be identified as as HKP or HKPS - within the Python Code. The ``hkp4py`` module will rewrite these - appropriately when the connection is made to the server. - -.. [6] - Okay, Emacs might not necessarily qualify as a basic tool, but it is - common enough that having it installed on a system isn\'t too great - an expectation, nor is it difficult to add to most POSIX systems, - even if the users of those systems do not personally use it. |