So, all this seems to indicate that we are way, way over-analyzing this, when all the solutions are in fact relatively simple. In fact, I'm inclined to say that the message about cascade ciphers was just ambient whiteboard scribbles and not even relevant at all.
So, since Surface Tension Uncut went retail I came across a pinboard texture that I didn't see anywhere else, yet. Right after the helipad battle there's a security booth to the left, you can enter it. There's some magnum ammo and a pinboard. nothing to peculiar, except this paper:
wherease everything else is unreadable, this clearly says "page 428". Did anyone catch this one, yet? I never saw it anywhere.
What could it refer to? Maybe a forum page on some other forum that may contain a clue that has been overlooked? Or a page of a book? What are your thoughts on this?
It's been in the game since the 2012 mod release. The texture is found in materials\models\props_am\post_boardpapers_08.vtf.
As far as AM goes, there's at least one direct reference to AM in one of the clues. In Dr. J. Welsh's diary log note, he writes that he "got a call from Dr Stone over in Sector C".