AEAD cipher mode implementation is based on that used for AES:

  https://tools.ietf.org/html/rfc5116

TLS GCM cipher suites as specified in:

  https://tools.ietf.org/html/rfc6209Reviewed-by: NPaul Dale <paul.dale@oracle.com>
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4287)