Issue #20951: SSLSocket.send() now raises either SSLWantReadError or SSLWantWriteError on a non-blocking socket if the operation would block. Previously, it would return 0.

Patch by Nikolaus Rath.

Issue #19940: ssl.cert_time_to_seconds() now interprets the given time string in the UTC timezone (as specified in RFC 5280), not the local timezone.

Patch by Akira.

Issue #20896: ssl.get_server_certificate() now uses PROTOCOL_SSLv23, not PROTOCOL_SSLv3, for maximum compatibility.

Closes #21043 by updating the documentation to remove specific CA
organizations and update the text to no longer need to tell you to
download root certificates, but instead use the OS certificates
avaialble through SSLContext.load_default_certs.

Closes #21013 by modfying ssl.create_default_context() to:

* Move the restricted ciphers to only apply when using
  ssl.Purpose.CLIENT_AUTH. The major difference between restricted and not
  is the lack of RC4 in the restricted. However there are servers that exist
  that only expose RC4 still.
* Switches the default protocol to ssl.PROTOCOL_SSLv23 so that the context
  will select TLS1.1 or TLS1.2 if it is available.
* Add ssl.OP_NO_SSLv3 by default to continue to block SSL3.0 sockets
* Add ssl.OP_SINGLE_DH_USE and ssl.OP_SINGLE_ECDG_USE to improve the security
  of the perfect forward secrecy
* Add ssl.OP_CIPHER_SERVER_PREFERENCE so that when used for a server side
  socket the context will prioritize our ciphers which have been carefully
  selected to maximize security and performance.
* Documents the failure conditions when a SSL3.0 connection is required so
  that end users can more easily determine if they need to unset
  ssl.OP_NO_SSLv3.

Issue #20913: improve the SSL security considerations to first advocate using create_default_context().

Closes #20995 by Enabling better security by prioritizing ciphers
such that:

* Prefer cipher suites that offer perfect forward secrecy (DHE/ECDHE)
* Prefer ECDHE over DHE for better performance
* Prefer any AES-GCM over any AES-CBC for better performance and security
* Then Use HIGH cipher suites as a fallback
* Then Use 3DES as fallback which is secure but slow
* Finally use RC4 as a fallback which is problematic but needed for
  compatibility some times.
* Disable NULL authentication, NULL encryption, and MD5 MACs for security
  reasons

Patch by Tshepang Lekhonkhobe, reviewed by Georg Brandl.

Issue #19422: Explicitly disallow non-SOCK_STREAM sockets in the ssl module, rather than silently let them emit clear text data.

Also remove some extra blank lines in the ssl doc acctions for tls1.1/1.2,
and reflow a paragraph.

with server_hostname on handshake.

a new SSLContext object with secure default settings.

certificates from default stores or system stores. By default the method
loads CA certs for authentication of server certs.

The patch removes the verify_flags feature on Mac OS X 10.4 with OpenSSL 0.9.7l 28 Sep 2006.

Also change the argument name to the same name as getpeercert()

CRL enumeration are now two functions. enum_certificates() also returns
purpose flags as set of OIDs.

of the context in order to enable certification revocation list (CRL)
checks or strict X509 rules.

and CRL distribution points.

to load CA certificates and CRL from memory. It supports PEM and DER
encoded strings.

for security reasons.  It now doesn't match multiple wildcards nor wildcards
inside IDN fragments.

Issue #19095: SSLSocket.getpeercert() now raises ValueError when the SSL handshake hasn't been done.

get_ca_list() lists all loaded CA certificates and cert_store_stats() returns
amount of loaded X.509 certs, X.509 CA certs and CRLs.

the default locations for cafile and capath.

Thanks to David D Lowe for reporting.

Fix a crash when setting a servername callback on a SSL server socket and the client doesn't send a server name.
Patch by Kazuhiro Yoshida.
(originally issue #8109)