OK so setting up SSL on my server and I would like admin covered by SSL and also the checkout process - now I seem to have 3 locations to play with within configure and not sure on the 3rd one..

admin/includes/configure.php

Code:
// secure webserver for admin?  Valid choices are 'true' or 'false' (including quotes).
  define('ENABLE_SSL_ADMIN', 'true');

  // secure webserver for storefront?  Valid choices are 'true' or 'false' (including quotes).
  define('ENABLE_SSL_CATALOG', 'true');
What does the 2nd one means the WHOLE catalog or just checkout section, because I then have:

includes/configure.php
Code:
  // Use secure webserver for checkout procedure?
  define('ENABLE_SSL', 'true');
so its just the 2nd one that I am unsure what its there for needed etc?

Thanks
Sarah