File Content: openssl.rst .. hazmat:: OpenSSL binding =============== .. currentmodule:: cryptography.hazmat.bindings.openssl.binding These are `CFFI`_ bindings to the `OpenSSL`_ C library. Cryptography supports OpenSSL version 1.0.1 and greater. .. class:: cryptography.hazmat.bindings.openssl.binding.Binding() This is the exposed API for the OpenSSL bindings. It has two public attributes: .. attribute:: ffi This is a ``cffi.FFI`` instance. It can be used to allocate and otherwise manipulate OpenSSL structures. .. attribute:: lib This is a ``cffi`` library. It can be used to call OpenSSL functions, and access constants. .. classmethod:: init_static_locks Enables the best available locking callback for OpenSSL. See :ref:`openssl-threading`. .. _openssl-threading: Threading --------- ``cryptography`` enables OpenSSLs `thread safety facilities`_ in two different ways depending on the configuration of your system. Normally the locking callbacks provided by your Python implementation specifically for OpenSSL will be used. However, if you have linked ``cryptography`` to a different version of OpenSSL than that used by your Python implementation we enable an alternative locking callback. This version is implemented in Python and so may result in lower performance in some situations. In particular parallelism is reduced because it has to acquire the GIL whenever any lock operations occur within OpenSSL. .. _`CFFI`: https://cffi.readthedocs.io .. _`OpenSSL`: https://www.openssl.org/ .. _`thread safety facilities`: https://www.openssl.org/docs/man1.0.2/crypto/threads.html Submit