[SCHiM]

I've got this idea that, given some R&D and technological advancements, an advanced military could drop 'dust sensors' over a future battlefield, or entire country.

Each particle of dust is a tiny computer with simple sensors, near field laser beam directed stealth communication node, FOF identification sensor, and maybe more. Soldiers could plug into this network (all properly encrypted, yadayada) en see and listen to the enemy. Dust covered vehicles could be tracked as long as they stay in a well-dusted area.

The idea is not that the enemy cannot see that you've 'dusted' their country/battlefield, but that you've dropped so much of this self-organizing sensor dust that they cannot block it all.

I'm assuming that the dust could be radiation hardened against EMP or other area of effect 'cleanup' measures, and that they are powerful enough to run proper cryptographic code, to ensure proper functioning of FOF and the communications.

[detritus]

I've long suspected that this route would be a much more likely path for an interested alien civilisation otherwise disinclined to make contact with us to take.

I also suspect that at least some insects have been utilised for similar intent. The trouble is in figuring out which ones... .

[EvanAnderson]

Neal Stephenson's "The Diamond Age" has some discussion of nano-machine "dusts" and the inevitable arms race when opposing factions both use them.