File Content: index.rst X.509 ===== X.509 is an ITU-T standard for a `public key infrastructure`_. X.509v3 is defined in :rfc:`5280` (which obsoletes :rfc:`2459` and :rfc:`3280`). X.509 certificates are commonly used in protocols like `TLS`_. .. toctree:: :maxdepth: 2 tutorial reference .. _`public key infrastructure`: https://en.wikipedia.org/wiki/Public_key_infrastructure .. _`TLS`: https://en.wikipedia.org/wiki/Transport_Layer_Security Submit