Secure directory

[zingmatter]

I want to place image and zip files in a directory that cannot be accessed by the public but can be accessed by an internal link, i.e.

<a href="http://www.mydomain.com/private_files/image1.jpg">image</a>
won't work (or by typing the above into the browser address bar), but
<a href="private_files/image1.jpg">image</a> will work.

Is this what a secure directory does.

Any advice, thanks