If you can't get the ssl protocol as a registered transport protocol even though you has add the extension=php_openssl.dll line on php.ini, maybe you haven't the libeay32.dll and / or ssleay32.dll files on your installation or in system32 folder.
stream_get_transports — Retrieve list of registered socket transports
Returns an indexed array containing the name of all socket transports available on the running system.
Returns an indexed array of socket transports names.
Exemplo #1 Using stream_get_transports()
$xportlist = stream_get_transports();
O exemplo acima irá imprimir algo similar à:
Array (  => tcp  => udp  => unix  => udg )