Delay-based PUF for Chiplets to Verify System Integrity

New technical paper titled “Know Time to Die – Integrity Checking for Zero Trust Chiplet-based Systems Using Between-Die Delay PUFs” by researchers at University of Massachusetts, Amherst MA,

Abstract (partial):
“In this paper we propose a delay-based PUF for chiplets to verify system integrity. Our technique allows a single chiplet to initiate a protocol with its neighbors to measure unique variations in the propagation delays of incoming signals as part of an integrity check. We prototype our design on Xilinx Ultrascale+ FPGAs, which are constructed as multi-die systems on a silicon interposer, and which also emulate the general features of other industrial chiplet interfaces. We perform experiments on, and compare data from, dozens of Ultrascale+ FPGAs by making use of Amazon’s Elastic Compute Cloud (EC2) F1 instances as a testing platform. The PUF cells are shown to reject clock and temperature variation as common mode, and each cell produces approximately 5 ps of unique delay variation. For a design with 144 PUF cells, we measure the mean within-class and between-class distances to be 68.3 ps and 847.7 ps, respectively. The smallest between-class distance of 686.0 ps exceeds the largest within-class distance of 124.0 ps by more than 5x under nominal conditions, and the PUF is shown to be resilient to environmental changes. Our findings indicate the PUF can be used for authentication, and is potentially sensitive enough to detect picosecond-scale timing changes due to tampering.”

Find the technical paper here. Published June 2022.

Deric, A., & Holcomb, D. (2022). Know Time to Die – Integrity Checking for Zero Trust Chiplet-based Systems Using Between-Die Delay PUFs. IACR Transactions on Cryptographic Hardware and Embedded Systems, 2022(3), 391–412. https://doi.org/10.46586/tches.v2022.i3.391-412.

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