InterPUF: Distributed Authentication via Physically Unclonable Functions and Multi-party Computation for Reconfigurable Interposers

Abstract: Modern system-in-package (SiP) platforms increasingly adopt reconfigurable interposers to enable plug-and-play chiplet integration across heterogeneous multi-vendor ecosystems. However, this flexibility introduces severe trust challenges, as traditional authentication schemes fail to scale or adapt in decentralized, post-fabrication programmable environments. This paper presents InterPUF, a compact and scalable authentication framework that transforms the interposer into a distributed root of trust. InterPUF embeds a route-based differential delay physically unclonable function (PUF) across the reconfigurable interconnect and secures authentication using multi-party computation (MPC), ensuring raw PUF signatures are never exposed. Our hardware evaluation shows only 0.23% area and 0.072% power overhead across diverse chiplets while preserving authentication latency within tens of nanoseconds. Simulation results using pyPUF confirm strong uniqueness, reliability, and modeling resistance under process, voltage, and temperature variations. By combining interposer-resident PUF primitives with cryptographic hashing and collaborative verification, InterPUF enforces a minimal-trust authentication model without relying on a centralized anchor.