mirror of
https://github.com/saymrwulf/cryptography.git
synced 2026-05-14 20:37:55 +00:00
90 lines
4.3 KiB
ReStructuredText
90 lines
4.3 KiB
ReStructuredText
Frequently asked questions
|
|
==========================
|
|
|
|
``cryptography`` failed to install!
|
|
-----------------------------------
|
|
|
|
If you are having issues installing ``cryptography`` the first troubleshooting
|
|
step is to upgrade ``pip`` and then try to install again. For most users this will
|
|
take the form of ``pip install -U pip``, but on Windows you should do
|
|
``python -m pip install -U pip``. If you are still seeing errors after upgrading
|
|
and trying ``pip install cryptography`` again, please see the :doc:`/installation`
|
|
documentation.
|
|
|
|
How does ``cryptography`` compare to NaCl (Networking and Cryptography Library)?
|
|
--------------------------------------------------------------------------------
|
|
|
|
While ``cryptography`` and `NaCl`_ both share the goal of making cryptography
|
|
easier, and safer, to use for developers, ``cryptography`` is designed to be a
|
|
general purpose library, interoperable with existing systems, while NaCl
|
|
features a collection of hand selected algorithms.
|
|
|
|
``cryptography``'s :ref:`recipes <cryptography-layout>` layer has similar goals
|
|
to NaCl.
|
|
|
|
If you prefer NaCl's design, we highly recommend `PyNaCl`_.
|
|
|
|
Why use ``cryptography``?
|
|
-------------------------
|
|
|
|
If you've done cryptographic work in Python before you have likely encountered
|
|
other libraries in Python such as *M2Crypto*, *PyCrypto*, or *PyOpenSSL*. In
|
|
building ``cryptography`` we wanted to address a few issues we observed in the
|
|
legacy libraries:
|
|
|
|
* Extremely error prone APIs and insecure defaults.
|
|
* Use of poor implementations of algorithms (i.e. ones with known side-channel
|
|
attacks).
|
|
* Lack of maintenance.
|
|
* Lack of high level APIs.
|
|
* Lack of PyPy and Python 3 support.
|
|
* Absence of algorithms such as
|
|
:class:`AES-GCM <cryptography.hazmat.primitives.ciphers.modes.GCM>` and
|
|
:class:`~cryptography.hazmat.primitives.kdf.hkdf.HKDF`.
|
|
|
|
Compiling ``cryptography`` on macOS produces a ``fatal error: 'openssl/aes.h' file not found`` error
|
|
----------------------------------------------------------------------------------------------------
|
|
|
|
This happens because macOS 10.11 no longer includes a copy of OpenSSL.
|
|
``cryptography`` now provides wheels which include a statically linked copy of
|
|
OpenSSL. You're seeing this error because your copy of pip is too old to find
|
|
our wheel files. Upgrade your copy of pip with ``pip install -U pip`` and then
|
|
try install ``cryptography`` again.
|
|
|
|
If you are using PyPy, we do not currently ship ``cryptography`` wheels for
|
|
PyPy. You will need to install your own copy of OpenSSL -- we recommend using
|
|
Homebrew.
|
|
|
|
Starting ``cryptography`` using ``mod_wsgi`` produces an ``InternalError`` during a call in ``_register_osrandom_engine``
|
|
-------------------------------------------------------------------------------------------------------------------------
|
|
|
|
Upgrade to the latest ``cryptography`` and this issue should be resolved.
|
|
|
|
``cryptography`` raised an ``InternalError`` and I'm not sure what to do?
|
|
-------------------------------------------------------------------------
|
|
|
|
Frequently ``InternalError`` is raised when there are errors on the OpenSSL
|
|
error stack that were placed there by other libraries that are also using
|
|
OpenSSL. Try removing the other libraries and see if the problem persists.
|
|
If you have no other libraries using OpenSSL in your process, or they do not
|
|
appear to be at fault, it's possible that this is a bug in ``cryptography``.
|
|
Please file an `issue`_ with instructions on how to reproduce it.
|
|
|
|
Installing ``cryptography`` fails with ``ImportError: No module named setuptools_ext``
|
|
--------------------------------------------------------------------------------------
|
|
|
|
Your ``cffi`` package is out of date. ``pip install -U cffi`` to update it.
|
|
|
|
Installing cryptography with OpenSSL 0.9.8 or 1.0.0 fails
|
|
---------------------------------------------------------
|
|
|
|
The OpenSSL project has dropped support for the 0.9.8 and 1.0.0 release series.
|
|
Since they are no longer receiving security patches from upstream,
|
|
``cryptography`` is also dropping support for them. To fix this issue you
|
|
should upgrade to a newer version of OpenSSL (1.0.1 or later). This may require
|
|
you to upgrade to a newer operating system.
|
|
|
|
.. _`NaCl`: https://nacl.cr.yp.to/
|
|
.. _`PyNaCl`: https://pynacl.readthedocs.io
|
|
.. _`WSGIApplicationGroup`: https://modwsgi.readthedocs.io/en/develop/configuration-directives/WSGIApplicationGroup.html
|
|
.. _`issue`: https://github.com/pyca/cryptography/issues
|