The world’s smallest and thinnest RFID tags have been introduced by Hitachi, measuring just 0.05 x 0.05 millimeters.

The new “powder type” chips have a 128-bit ROM for storing a unique 38 digit number and could be worked into any product to assure theft of consumer goods would be practically impossible.

These devices could also be used to identify and track people. For example, suppose you participated in some sort of protest or other organized activity. If police agencies sprinkled these tags around, every individual could be tracked and later identified at leisure, with powerful enough tag scanners.