What files need to go into secure directory?

If I call a single PHP file that in turn uses GET's and POST's to build the HTML page as well as process other data and store it in开发者_运维技巧 SESSION, do I need to mirror the entire site into an HTTPS capable directory or does only the page being called need to be in the directory?

So for example my computer sends my name via POST to the server and specifically Index.php.

If the address of Index.php is is the data secure going to the server? Is the data returning, most specifically the SESSION data, also secure?

Also I apologize if this quest has been answered a hundred times, for some reason I could not think of the proper search terms to find the answer.

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do I need to mirror the entire site into an HTTPS capable directory or does only the page being called need to be in the directory?

No. Webserver can be set up so it watches to the same directory for both http and https

If the address of Index.php is is the data secure going to the server?

If it is a https protocol specified in the url - then all the traffic (request from client to server and response from server to client) between client and serever is crypted.

Is the data returning, most specifically the SESSION data, also secure?

Session data is never sent to client. It is stored on the server.