Protecting Copyrighted Content in Storyline Projects

Hi, I'm looking for some help. I'm producing some content on Storyline, and the "product" is going to be given to different institutions. The content uses photos with copyrighted rights that are owned by our main client.

At first, my team and I considered providing the ZIP file to be uploaded in the LMS, but we've discovered that once the folder is opened, the multimedia content (in our case, the photos) is accessible.

Since we want to avoid access to these contents, is there a way to protect/encrypt the ZIP that goes into the LMS to prevent access to the contents? 

Thank you.