There are times when something is simply too small to tag it with existing technology, and that can be a serious problem when you're trying to fight counterfeits. MIT researchers might have a way to tag even the tiniest devices, though. They've created a very small (0.002 square inches) ID chip that's still secure enough to protect sensitive data. The team managed the feat through a monolithic chip powered solely by light, with antennas that use beam steering and RFID-style (but terahertz-level) backscatter to wirelessly send info to a nearby reader without requiring energy. These keep the design small while reserving enough electricity for encryption.