Very interesting problem, and a solution class that uses additive/subtractive signals – sort of like and RF version of noise canceling headset technology in a way:
Millions of Americans have implantable medical devices, from pacemakers and defibrillators to brain stimulators and drug pumps; worldwide, 300,000 more people receive them every year. Most such devices have wireless connections, so that doctors can monitor patients’ vital signs or revise treatment programs. But recent research has shown that this leaves the devices vulnerable to attack: In the worst-case scenario, an attacker could kill a victim by instructing an implantable device to deliver lethal doses of medication or electricity.
At the Association for Computing Machinery’s upcoming Sigcomm conference, researchers from MIT and the University of Massachusetts-Amherst (UMass) will present a new system for preventing such attacks. The system would use a second transmitter to jam unauthorized signals in an implant’s operating frequency, permitting only authorized users to communicate with it. Because the jamming transmitter, rather than the implant, would handle encryption and authentication, the system would work even with existing implants.
The researchers envision that the jamming transmitter — which they call a shield — would be small enough to wear as a necklace or a watch. A device authorized to access the implant would send encrypted instructions to the shield, which would decode and relay them.
Wondering if the tightly coupled antenna arrays have other applications?