Novel chip can protect devices from hardware viruses

Scientists, including of Indian origin, are developing a new chip that can detect malicious circuitry and prevent hardware viruses from sabotaging medical devices, and financial, military or government electronics.

With the outsourcing of microchip design and fabrication a worldwide USD 350 billion business, bad actors along the supply chain have many opportunities to install malicious circuitry in chips.

These "Trojan horses" look harmless but can allow attackers to sabotage public infrastructure, healthcare devices, and financial, military or government electronics.

Researchers including Siddharth Garg, assistant professor at the New York University, are developing a chip with both an embedded module that proves that its calculations are correct and an external module that validates the first module's proofs.

While software viruses are easy to spot and fix with downloadable patches, deliberately inserted hardware defects are invisible and act surreptitiously.

For example, a secretly inserted "back door" function may allow attackers to alter or take over a device at a specific time.

Garg's configuration, an example of an approach called "verifiable computing" (VC), keeps tabs on a chip's performance and can spot telltale signs of Trojans.

The ability to verify has become vital in an electronics age without trust. "Gone are the days when a company could design, prototype, and manufacture its own chips. Manufacturing costs are now so high that designs are sent to offshore foundries, where security cannot always be assured," researchers said.

Under the system proposed by researchers, the verifying processor can be fabricated separately from the chip.

"Employing an external verification unit made by a trusted fabricator means that I can go to an untrusted foundry to produce a chip that has not only the circuitry-performing computations, but also a module that presents proofs of correctness," said Garg.

The chip designer then turns to a trusted foundry to build a separate, less complex module - an application-specific integrated circuit (ASIC), whose sole job is to validate the proofs of correctness generated by the internal module of the untrusted chip.

Garg said that this arrangement provides a safety net for the chip maker and the end user. "Under the current system, I can get a chip back from a foundry with an embedded Trojan. It might not show up during post-fabrication testing, so I'll send it to the customer," said Garg.

"But two years down the line it could begin misbehaving. The nice thing about our solution is that I don't have to trust the chip because every time I give it a new input, it produces the output and the proofs of correctness, and the external module lets me continuously validate those proofs," he said.