This is the first story-based entry I've come across so far. Great, layered use of the theme.
I love that jaunty music. Gives you the proper creeps.
I think it'd be great if you can get a clue in the cheaper nodes too, just to give more illusion of progress. (Although story-wise, it makes sense that the important info is hidden behind harder-to-hack nodes.)
I couldn't figure out the 2nd number so I kept guessing using the other three that I know. Maybe you can also punish players for guessing randomly. :)