Researchers at the Massachusetts Institute of Technology have created a chip-fabrication technique that could improve cryptographic security by letting two hardware devices authenticate each other directly, without storing secret keys on an external server. Traditional physical-unclonable-function (PUF) systems use small, unavoidable manufacturing variations in chips as unique identifiers, but they rely on servers to hold cryptographic data for later verification. That dependence introduces potential vulnerabilities and additional memory and computational overhead. The new method embeds a shared PUF directly into matched chips during fabrication, eliminating the need for third-party storage and reducing attack surfaces while lowering energy costs for authentication in power-constrained systems.
The innovation works by deliberately inducing correlated microscopic randomness across adjacent complementary metal–oxide–semiconductor (CMOS) chips before they are separated from a silicon wafer. As the fabrication process introduces tiny variations, each chip acquires a unique “fingerprint.” By modifying transistor breakdown properties and creating paired structures, engineers produce two chips with a nearly identical PUF. These paired identifiers allow each chip to recognize and authenticate the other directly. Once diced from the wafer, the chips can perform cryptographic handshakes without reaching out to external servers for key verification, which improves both privacy and efficiency.
Lead author Eunseok Lee and colleagues say the approach could be especially useful in applications where devices need quick, secure mutual authentication under strict energy limitations—for example, between a tiny ingestible sensor and a paired wearable patch in medical monitoring. Because the secret remains confined to the silicon itself and is never exposed outside the hardware, the security model is inherently more robust than schemes that rely on external key repositories. The research, presented at the IEEE International Solid-States Circuits Conference, demonstrates the potential of shared PUFs to simplify secure communications between paired embedded devices.