Function and Shortcode of Default User ID (user ID?)

Now that I have upgraded to MemberMouse plugin for better integration with Post Affiliate Pro App, the app now creates affiliates with the default referral ID. Usually I would try and force the app to pull only the 'blog path' as referral ID, but this seems too difficult at the moment. (mainly because MemberMouse makes my PAP App to ignore the WP username and only pull some original id.. the id pulled looks like this for reference: d203dd49). *I hope I'm using the phrase User ID correctly.

Is there a way to have a shortcode that will display the alphanumeric user original ID?

Here is an example of the shortcode I was using to place my username in all my user banners for reference:

// Blog Path - [blog_path_ref] or [blog_path_ref main_site=""]
function blog_path_ref_func( $atts ) {
global $current_blog;
$blog_path = trim( $current_blog->path, '/' );
extract( shortcode_atts( array(
'main_site' => network_site_url()
), $atts));

return $main_site."?ref={$blog_path}";
add_shortcode( 'blog_path_ref', 'blog_path_ref_func' );

Any help to make this into the original user id (not username), would be greatly appreciated