Using a patient's heartbeat as a security identifier could thwart hackers from tampering with implanted devices like wireless defibrillators and insulin pumps. MIT Technology Review reports that researchers from Rice University and the security company RSA developed a simple system that relies on the idea. First, a doctor would hold a device against the patient's body to take a direct heartbeat reading. The device then compares that reading to another one relayed in a wireless signal from the implant, and that exchange is encrypted. Once the device confirms a match, a doctor can then reprogram the implant. Story