Creating a secure link

You may have cause to protect certain content on your site, but do not want to integrate full user authentication to allow access to that content. One way of enabling this is to use the secure_link module of NGINX. By passing the --with-http_secure_link_module switch at compile time, you get access to the secure_link_secret directive, and its corresponding variable, $secure_link.

The secure_link module works by computing the MD5 hash of a link concatenated with a secret word. If the hash matches that value found in the URI, the $secure_link variable is set to the portion of the URI after the hash. If there is no match, $secure_link is set to the empty string.

One possible scenario is to generate a page of download links using a secret word. This word is then placed in the NGINX configuration to enable access to these links. The word and page are replaced periodically to prevent saved links from being called again at a later time. The following example illustrates this...