https://www.sciencedaily.com/releases/2018/06/180614212921.htm

The team developed a real-time end-to-end system called PHADE to allow this process, known as private human addressing. While traditional data transmission protocols need to first learn the destination's IP or MAC address, this system uses motion patterns as the address code for communication. The smartphones then locally make their own decisions on whether to accept a message.

The PHADE system works using a server to receive video streams from cameras to track people. The camera builds a packet by linking a message to the address code and broadcasts the packet. Upon receiving the packet, a mobile device of each of the targets uses sensors to extract its owner's behavior and follow the same transformation to derive a second address code. If the second address code matches with the address code in the message, the mobile device automatically delivers the message to its owner.