what is the meaning of the numbers at the back of the digital fortress book/after the epilogue page?

1- In the last page of the book there are the following numbers:
128-10-93-85-10-128-98-112-6-6-25-126-39-1-68-78
2- If you go to the corresponding chapter and replace the number by the first letter of the beginnig of that chapter an rearrange them in what is called a Cesar Square, a 4 by 4 square, (the author gives you the explanation on the book) will come up to the following:
W E C G
E W H Y
A A I O
R T N U
3- and then read from top to bottom, left to right it reads:
"WE ARE WATCHING YOU"

that's "we are watching you"
he used ceasar's box in that one.:), it took a long time for me to figure that out though but with a flashlight, pen and some clues i got out of the story, the code finally broke.

And by 'WE', Danny is referring to the NSA?