Bokodes are better bar codes that pack as much information as RFID tags, but are secure from hackers and much, much smaller. Check you this video about how MIT packed coded information behind a three millimeter illuminated microdot that can be read with a cell phone camera.
MIT's bokode is named after the Japanese term "bokeh," which refers to the image of a round blob that results when a camera is out of focus. MIT researchers reversed that process by encoding the microdot's blob-like image based on the angles at which rays emerge from the lens--an encoding that allows the out-of-focus camera to recombine the rays into the original. Check out all the details in the video!