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As quantum computers advance, they are expected to be able to break tried-and-true security schemes that currently keep most sensitive data secure from attackers. Scientists and policymakers are working to design and implement post-quantum cryptography to defend against these future attacks.
MIT researchers have developed an ultra-efficient microchip that can bring post-quantum cryptography techniques to wireless biomedical devices, like pacemakers and insulin pumps. Such wearable, ingestible, or implantable devices are usually too power-constrained to implement these computationally demanding security protocols.
Their tiny chip, which is about the size of a very fine needle tip, also includes built-in protections against physical hacking attempts that can bypass encryption to steal user data, such as a patient’s social security number or device credentials. Compared to prior designs, the new technology is more than an order of magnitude more energy-efficient.
In the long run, the new chip could enable next-generation wireless medical devices to maintain strong security even as quantum computing becomes more prevalent. In addition, it could be applied to many types of resource-constrained edge devices, like industrial sensors and smart inventory tags.
“Tiny edge devices are everywhere, and biomedical devices are often the most vulnerable attack targets because power constraints prevent them from having the most advanced levels of security. We’ve demonstrated a very practical hardware solution to secure the privacy of patients,” says Seoyoon Jang, an MIT electrical engineering and computer science (EECS) graduate student and lead author of a paper on the chip.
Jang is joined on the paper by Saurav Maji PhD ’23; visiting scholar Rashmi Agrawal; EECS graduate students Hyemin Stella Lee and Eunseok Lee; Giovanni Traverso, an associate professor of mechanical engineering at MIT, a gastroenterologist at Brigham and Women’s Hospital, and an associate member of the Broad Institute of MIT and Harvard; and senior author Anantha Chandrakasan, MIT provost and the Vannevar Bush Professor of Electrical Engineering and Computer Science. The research was recently presented at the IEEE Custom Integrated Circuits Conference.
Stronger security
A large percentage of wireless biomedical devices, like ingestible biosensors for health monitoring, currently lack strong protection due to the computational demands of existing security protocols, Jang says.
But the complexity of post-quantum cryptography (PQC) can increase power consumption by two or three orders of magnitude.
Implementing PQC is of paramount importance, since regulatory bodies like the National Institute of Standards and Technology (NIST) will soon begin phasing out traditional cryptography protocols in favor of stronger PQC algorithms. In addition, some industry leaders believe rapid advances in quantum hardware make PQC implementation even more urgent.
To bring these power-hungry PQC protocols to wireless biomedical devices, the MIT researchers designed a customized microchip, known as an application-specific integrated circuit (ASIC), that greatly reduces energy overhead while guaranteeing the highest level of security.
“PQC is very secure algorithmically, but making a device resilient against physical attacks usually requires additional countermeasures that pump up the energy consumption at least two or three times. We want our chip to be robust to both security threats in a very lightweight manner,” Jang says.
A multi-pronged approach
To accomplish these goals, the researchers incorporated several design features into the chip.
First, they implemented two different PQC schemes to enhance robustness and “future-proof” their device in case one scheme is later proven to be insecure. To boost energy efficiency, they applied techniques that enable the PQC algorithms to share as much of the chip’s computational resources as possible.
Second, the researchers designed a highly efficient, on-chip true random number generator. This device continually generates random numbers to use for secret keys, which is essential to implement PQC.
Their on-chip design improves energy efficiency and security over standard approaches that usually receive random numbers from an external chip.
Third, they implemented countermeasures that prevent a type of physical hacking attempt, called a power side-channel attack, but only on the most vulnerable parts of the PQC protocols.
In power side-channel attacks, hackers steal secret information by analyzing the power consumption of a device while it processes data. The MIT researchers added just enough redundancy to the PQC operations to ensure the chip is protected from these types of attacks.
Fourth, they designed an early fault-detection mechanism so the chip will abort operations early if it detects a voltage glitch.
Wireless biomedical devices often have erratic power supplies, so they are susceptible to glitches that can cause an entire security procedure to fail. The MIT approach saves energy by stopping the chip from running a doomed procedure to completion.
“At the end of the day, because of the techniques we utilized, we can apply these post-quantum cryptography primitives while adding nothing to the overhead, with the added benefit of robustness to side-channel attacks,” Jang says.
Their device achieved between 20 to 60 times higher energy efficiency than all other PQC security techniques they compared it to, with a more compact area than many existing chips.
“As we transition into post-quantum approaches, providing strong security for even the most resource-limited devices is essential. This work shows that robust cryptographic protection for biomedical and edge devices can be achieved alongside energy efficiency and programmability,” says Chandrakasan.
In the future, the researchers want to apply these techniques to other vulnerable applications and energy-constrained devices.
This research was funded, in part, by the U.S. Advanced Research Projects Agency for Health.
