Challenge HN: Can you decrypt these messages? [pdf]

This document is available in higher fidelity, and with greater context, here: http://www.cufon.org/pdf/4_NSA_Tech_Journal_Articles.pdf

They comprise an exercise in interpreting coded messages, and are not intended to be interpreted as a genuine ET transmission.

Is this real or just an exercise? (sorry if that sounds stupid - you never know what kind of shit gets posted here)

It's real.

Meta-question: How do you include two different links (pdf/scribd) in the submission URL?

Scribd links automatically generated for PDFs. I wonder if they check for mimetype, or they just assume it from the extension..

scribd is a YC company. Any pdf submissions automatically get scribd.

Scribd link is auto added by HN system if the original URL ends with '.pdf'.