Remotely hacking a pacemaker or insulin pump should be impossible, but sadly it isn't. It puts the millions of people who use wireless medical implants at potential risk. Researchers at Rice University believe they have a solution: a touch-based device that will use a person's own heartbeat as a password to permit or deny access to their implant.

Making wireless medical implants totally secure is tricky business because of the need to make them instantly accessible to emergency medical personnel, who might need the information to save lives. "The current generation of devices do not typically have security functions," Rice electrical and computer engineer Farinaz Koushanfar tells Gizmag, "They can be hacked rather easily, once a hacker spends the time to figure out the communication protocol by eavesdropping on packages sent or received by the device."

Many known security measures can't be incorporated into IMDs because they are either too computationally intensive (which causes a power drain) or so tough that they affect emergency response times. The famous hacker Barnaby Jack, who was due to speak at the Black Hat conference earlier this year, planned to reveal his findings on security flaws in insulin pumps that would allow someone 300 feet away to release a fatal dose, before his unfortunate death. Hackers have shown that it's possible to change the software on a pacemaker, change the heart rate and even deliver shocks to the heart.

"The possibilities are endless," Koushanfar tells us. "Whatever function which can be remotely controlled from the wireless channel can be a subject to hack." Scientists have looked into solutions like wearable wireless signal jammers, identification numbers and secondary authentication to solve the problem. The Rice University team's approach calls for matching unique characteristics within a patient's heartbeat that requires software within the IMD to communicate with a programmer, an external touch device that emergency workers can carry.

The programmer device picks up the electrocardiogram (EKG) signature of the heart as soon as the medical technician touches the patient. It then compares the EKG signal with the IMD's signal and a matching result becomes the password that permits further access.

"The EKG is used as a biological source for generating instantaneous true random numbers which is shared between the device and the programmer who can touch the body," Koushanfar tells us."This truly random signal cannot be predicted or faked by somebody who is further away. An exciting contribution of our work is the introduction of secure algorithms for comparing the noisy EKG readings from the IMD and the programmer, without the possibility of having the values eavesdropped on the wireless channel."

It's secure from attacks, the researchers say, because the signal from a heartbeat differs every second, making it impossible for anyone else to use even moments later. "The duration of each heart beat can not be predicated completely by any modeling method – it will always have a random component it," Masoud Rostami, a graduate student on the team, tells Gizmag. "This is because the heart beat is governed by a very complex and chaotic system. We basically find and extract this random component."

It wasn't easy to develop as they had to sort out numerous challenges dealing with cutting out signal noises in the measurement process. The researchers say they settled on using EKG signals because they are already measured by many existing IMDs and can be accessed throughout a person's body. Called Heart-to-Heart (H2H), their authentication solution is easy to implement, they claim, because it can be introduced as a software update into the millions of IMDs already being used and only needs a little of the IMD's power. The technology can also applied to body area networks, they claim.

"It can probably be used in brain implants too, since they will be able to measure the heart rate in the brain area as well," adds Koushanfar whose team is in the process of getting the device approved by the Food and Drug Administration. They are also engaged in the process of contacting IMD companies to discuss integrating H2H in their design.

H2H was developed with Ari Juels, a former chief scientist at RSA Laboratories, a security company based in Massachusetts and is due to be presented at the Association for Computing Machinery’s Conference on Computer and Communications Security in Berlin in November. The research was supported by the Army Research Office and the Office of Naval Research.