ARM Chip Safeguards IoT Physical Security

UK chip maker ARM has produced a processor for connected devices in homes or publicly accessible places that includes protections against physical attacks, as such chips increasingly carry out critical infrastructure tasks.

The physical safeguards in the Cortex M35-P, part of the Cortex-M range, could help protect smart streetlights in major cities or smart meters in residences or business premises, ARM said.

In the past, such protections could only be justified for the chips used for payment smartcards, said ARM’s vice president for IoT device intellectual property, Paul Williamson.

He said that “Internet of Things” (IoT) devices are handling higher-value data, while the tools and education necessary for physical attacks are becoming cheaper.

Smart grid protection

“As new use cases emerge, this protection won’t just be required for payment and identity applications, it will need to be integrated for use cases such as smart lighting, connected door locks, smart meters or automotive applications,” he wrote in an online post.

A hack into a single smart streetlight could potentially allow an attacker access to the smart grid of an entire city, ARM said.

Connected devices are often associated with network-based attacks that exploit poor security, such as the Mirai botnet, but Williamson said the new physical protections are aimed at making it more difficult and expensive to hack into chips in cases where the attacker has direct access or is in physical proximity.

In the former case attacks could include breaking a chip out of its packaging, while an attacker in close proximity to a chip could carry out side-channel attacks, which could involve observing factors such as a chip’s power consumption or electromagnetic field emission.

Side-channel attacks can, for example, allow an attacker to glean sensitive information during a cryptographic operation, Williamson said.

Smartcard-grade features

The Cortex M35-P is ARM’s first chip with tamper resistance that is designed into the chip and is based on ARM technology previously used in smartcards and credit cards, he said.

“By mitigating information leakage at the source, rather than looking for ways to hide or mask the leaking information, we have put an additional safeguard in place for protecting against evolving methods and analysis tools attackers might use to overcome traditional ‘information hiding’ tactics,” Williamson wrote.

It includes ARM’s TrustZone, which physically isolates sensitive data within the chip, and a safety package in support of ISO 26262 certification.

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