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Diffstat (limited to 'docs/hazmat/bindings/openssl.rst')
| -rw-r--r-- | docs/hazmat/bindings/openssl.rst | 19 |
1 files changed, 9 insertions, 10 deletions
diff --git a/docs/hazmat/bindings/openssl.rst b/docs/hazmat/bindings/openssl.rst index ac65aa97..ac9ccedf 100644 --- a/docs/hazmat/bindings/openssl.rst +++ b/docs/hazmat/bindings/openssl.rst @@ -33,16 +33,15 @@ OpenSSL version 1.0.1 and greater. 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. +``cryptography`` enables OpenSSLs `thread safety facilities`_ in several +different ways depending on the configuration of your system. For users on +OpenSSL 1.1.0 or newer (including anyone who uses a binary wheel) the OpenSSL +internal locking callbacks are automatically used. Otherwise, we first attempt +to use the callbacks provided by your Python implementation specifically for +OpenSSL. This will work in every case except where ``cryptography`` is linked +against a different version of OpenSSL than the one used by your Python +implementation. For this final case we have a C-based locking callback. .. _`CFFI`: https://cffi.readthedocs.io .. _`OpenSSL`: https://www.openssl.org/ -.. _`thread safety facilities`: https://www.openssl.org/docs/man1.0.2/crypto/threads.html +.. _`thread safety facilities`: https://www.openssl.org/docs/man1.0.2/man3/CRYPTO_THREADID_set_callback.html |