Installation ============ You can install ``cryptography`` with ``pip``: .. code-block:: console $ pip install cryptography Supported platforms ------------------- Currently we test ``cryptography`` on Python 2.7, 3.5+, PyPy 7.1+, and PyPy3 7.0 on these operating systems. * x86-64 CentOS 7.x * x86-64 Fedora (latest) * macOS 10.15 Catalina * x86-64 Ubuntu 16.04 and rolling * x86-64 Debian Stretch (9.x), Buster (10.x), Bullseye (11.x), and Sid (unstable) * x86-64 Alpine (latest) * 32-bit and 64-bit Python on 64-bit Windows Server 2019 We test compiling with ``clang`` as well as ``gcc`` and use the following OpenSSL releases: * ``OpenSSL 1.0.2-latest`` * ``OpenSSL 1.1.0-latest`` * ``OpenSSL 1.1.1-latest`` Building cryptography on Windows -------------------------------- The wheel package on Windows is a statically linked build (as of 0.5) so all dependencies are included. To install ``cryptography``, you will typically just run .. code-block:: console $ pip install cryptography If you prefer to compile it yourself you'll need to have OpenSSL installed. You can compile OpenSSL yourself as well or use `a binary distribution`_. Be sure to download the proper version for your architecture and Python (VC2010 works for Python 2.7 while VC2015 is required for 3.5 and above). Wherever you place your copy of OpenSSL you'll need to set the ``LIB`` and ``INCLUDE`` environment variables to include the proper locations. For example: .. code-block:: console C:\> \path\to\vcvarsall.bat x86_amd64 C:\> set LIB=C:\OpenSSL-win64\lib;%LIB% C:\> set INCLUDE=C:\OpenSSL-win64\include;%INCLUDE% C:\> pip install cryptography As of OpenSSL 1.1.0 the library names have changed from ``libeay32`` and ``ssleay32`` to ``libcrypto`` and ``libssl`` (matching their names on all other platforms). ``cryptography`` links against the new 1.1.0 names by default. If you need to compile ``cryptography`` against an older version then you **must** set ``CRYPTOGRAPHY_WINDOWS_LINK_LEGACY_OPENSSL`` or else installation will fail. If you need to rebuild ``cryptography`` for any reason be sure to clear the local `wheel cache`_. .. _build-on-linux: Building cryptography on Linux ------------------------------ ``cryptography`` ships ``manylinux`` wheels (as of 2.0) so all dependencies are included. For users on pip 8.1 or above running on a ``manylinux1`` or ``manylinux2010`` compatible distribution (almost everything except Alpine) all you should need to do is: .. code-block:: console $ pip install cryptography If you are on Alpine or just want to compile it yourself then ``cryptography`` requires a compiler, headers for Python (if you're not using ``pypy``), and headers for the OpenSSL and ``libffi`` libraries available on your system. Alpine ~~~~~~ Replace ``python3-dev`` with ``python-dev`` if you're using Python 2. .. code-block:: console $ sudo apk add gcc musl-dev python3-dev libffi-dev openssl-dev If you get an error with ``openssl-dev`` you may have to use ``libressl-dev``. Debian/Ubuntu ~~~~~~~~~~~~~ Replace ``python3-dev`` with ``python-dev`` if you're using Python 2. .. code-block:: console $ sudo apt-get install build-essential libssl-dev libffi-dev python3-dev RHEL/CentOS ~~~~~~~~~~~ .. code-block:: console $ sudo yum install redhat-rpm-config gcc libffi-devel python-devel \ openssl-devel Building ~~~~~~~~ You should now be able to build and install cryptography. To avoid getting the pre-built wheel on ``manylinux`` compatible distributions you'll need to use ``--no-binary``. .. code-block:: console $ pip install cryptography --no-binary cryptography Using your own OpenSSL on Linux ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Python links to OpenSSL for its own purposes and this can sometimes cause problems when you wish to use a different version of OpenSSL with cryptography. If you want to use cryptography with your own build of OpenSSL you will need to make sure that the build is configured correctly so that your version of OpenSSL doesn't conflict with Python's. The options you need to add allow the linker to identify every symbol correctly even when multiple versions of the library are linked into the same program. If you are using your distribution's source packages these will probably be patched in for you already, otherwise you'll need to use options something like this when configuring OpenSSL: .. code-block:: console $ ./config -Wl,--version-script=openssl.ld -Wl,-Bsymbolic-functions -fPIC shared You'll also need to generate your own ``openssl.ld`` file. For example:: OPENSSL_1.1.0E_CUSTOM { global: *; }; You should replace the version string on the first line as appropriate for your build. Static Wheels ~~~~~~~~~~~~~ Cryptography ships statically-linked wheels for macOS, Windows, and Linux (via ``manylinux``). This allows compatible environments to use the most recent OpenSSL, regardless of what is shipped by default on those platforms. Some Linux distributions (most notably Alpine) are not ``manylinux`` compatible so we cannot distribute wheels for them. However, you can build your own statically-linked wheels that will work on your own systems. This will allow you to continue to use relatively old Linux distributions (such as LTS releases), while making sure you have the most recent OpenSSL available to your Python programs. To do so, you should find yourself a machine that is as similar as possible to your target environment (e.g. your production environment): for example, spin up a new cloud server running your target Linux distribution. On this machine, install the Cryptography dependencies as mentioned in :ref:`build-on-linux`. Please also make sure you have `virtualenv`_ installed: this should be available from your system package manager. Then, paste the following into a shell script. You'll need to populate the ``OPENSSL_VERSION`` variable. To do that, visit `openssl.org`_ and find the latest non-FIPS release version number, then set the string appropriately. For example, for OpenSSL 1.0.2k, use ``OPENSSL_VERSION="1.0.2k"``. When this shell script is complete, you'll find a collection of wheel files in a directory called ``wheelhouse``. These wheels can be installed by a sufficiently-recent version of ``pip``. The Cryptography wheel in this directory contains a statically-linked OpenSSL binding, which ensures that you have access to the most-recent OpenSSL releases without corrupting your system dependencies. .. code-block:: console set -e OPENSSL_VERSION="VERSIONGOESHERE" CWD=$(pwd) virtualenv env . env/bin/activate pip install -U setuptools pip install -U wheel pip curl -O https://www.openssl.org/source/openssl-${OPENSSL_VERSION}.tar.gz tar xvf openssl-${OPENSSL_VERSION}.tar.gz cd openssl-${OPENSSL_VERSION} ./config no-shared no-ssl2 no-ssl3 -fPIC --prefix=${CWD}/openssl make && make install cd .. CFLAGS="-I${CWD}/openssl/include" LDFLAGS="-L${CWD}/openssl/lib" pip wheel --no-binary :all: cryptography Building cryptography on macOS ------------------------------ .. note:: If installation gives a ``fatal error: 'openssl/aes.h' file not found`` see the :doc:`FAQ ` for information about how to fix this issue. The wheel package on macOS is a statically linked build (as of 1.0.1) so for users with pip 8 or above you only need one step: .. code-block:: console $ pip install cryptography If you want to build cryptography yourself or are on an older macOS version, cryptography requires the presence of a C compiler, development headers, and the proper libraries. On macOS much of this is provided by Apple's Xcode development tools. To install the Xcode command line tools (on macOS 10.9+) open a terminal window and run: .. code-block:: console $ xcode-select --install This will install a compiler (clang) along with (most of) the required development headers. You'll also need OpenSSL, which you can obtain from `Homebrew`_ or `MacPorts`_. Cryptography does **not** support Apple's deprecated OpenSSL distribution. To build cryptography and dynamically link it: `Homebrew`_ .. code-block:: console $ brew install openssl@1.1 $ env LDFLAGS="-L$(brew --prefix openssl@1.1)/lib" CFLAGS="-I$(brew --prefix openssl@1.1)/include" pip install cryptography `MacPorts`_: .. code-block:: console $ sudo port install openssl $ env LDFLAGS="-L/opt/local/lib" CFLAGS="-I/opt/local/include" pip install cryptography You can also build cryptography statically: `Homebrew`_ .. code-block:: console $ brew install openssl@1.1 $ env CRYPTOGRAPHY_SUPPRESS_LINK_FLAGS=1 LDFLAGS="$(brew --prefix openssl@1.1)/lib/libssl.a $(brew --prefix openssl@1.1)/lib/libcrypto.a" CFLAGS="-I$(brew --prefix openssl@1.1)/include" pip install cryptography `MacPorts`_: .. code-block:: console $ sudo port install openssl $ env CRYPTOGRAPHY_SUPPRESS_LINK_FLAGS=1 LDFLAGS="/opt/local/lib/libssl.a /opt/local/lib/libcrypto.a" CFLAGS="-I/opt/local/include" pip install cryptography If you need to rebuild ``cryptography`` for any reason be sure to clear the local `wheel cache`_. .. _`Homebrew`: https://brew.sh .. _`MacPorts`: https://www.macports.org .. _`a binary distribution`: https://wiki.openssl.org/index.php/Binaries .. _virtualenv: https://virtualenv.pypa.io/en/latest/ .. _openssl.org: https://www.openssl.org/source/ .. _`wheel cache`: https://pip.pypa.io/en/stable/reference/pip_install/#caching