Enforce TLS v1.2 documentation

[btry]

Hi

I configured Mosquitto to accept TLS v1.2 only and reject TLS v1.0 or v1.1

The library works fine this way, but PHP os poorly documented about enforcing TLS v1.2 with Socket context. See this page : http://php.net/manual/en/function.stream-socket-enable-crypto.php

There is no mention of all constants available here http://php.net/manual/en/migration56.constants.php , especially STREAM_CRYPTO_METHOD_TLSv1_2_SERVER

Not configuring this crypto method in the socket context will prevent PHP from connecting to a Mosquitto instance configured to accelt only TLS v1.2.

I think a note in the README.md or a wiki page would be helpful to help users of your library ensure an aceptable level of security, as TLS < v1.2 is weak now.

[sskaje]

Hi @btry , do you mind creating wiki pages about this?

[btry]

Hi

I may provide the relevant configuration for Mosquitto, and a PHP snippet for such setup.