They yellow dots watermark output with printer identification information. I think this serves CDS, but has potential to be used/misused for so much more.
Sorry, I forgot that the printer dots were lingering in the HN consciousness- I was thinking of these things [0] (shown here [1] on the us $10, with little ones next to them to give apparent visual purpose) which I've also seen on non-currency things such as event/movie tickets iirc. Wikipedia suggests a scanning-hardware focus of the circles, as opposed to the software focus of the "Counterfeit Deterrence System" discussed in OP.
