Congratulations for figuring out the mystery message and the embedded URL! I hope you enjoyed figuring out what type of cipher I used and the decoding process. 

I'm Adam and I am the technical lead of National Security Agency's Science of Security (SoS) Program.  The program was established to advance foundational cybersecurity research so that everyone can use the theories and models to build a safe cyberspace. Look around this site and you'll see all the research done and other parts.  

The book used, the Trusted Computer System Evaluation Criteria, aka the Orange Book, was a book written in my organization back in 1983. Back then the org was known as the National Computer Security Center and now we are the Laboratory for Advanced Cybersecurity Research. As it is one of the most famous cybersecurity documents written, this is why I chose to use it here.

Now that you are here, please send me an email message on how you found the puzzle and your approach at decoding it.  Science.of.Security@uwe.nsa.gov

If you want to see the others, we have an index page. My favorite is the 2021. 

Adam