Delay-Based PUF Chiplet Interconnect Authentication
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Solution Overview
Problem
Systems-on-Chip (SoCs) with multiple chiplets face security risks due to increased flexibility and interconnect standardization, making them susceptible to attacks like die swapping, interface tampering, and man-in-the-middle attacks, as trust between untrusted chiplets cannot be assumed.
Innovation Solution
Implementing delay-based Physically Unclonable Functions (PUFs) to measure and compare signal delays between chiplets, using interposers to establish a unique signature for authentication and integrity verification, providing a zero-trust mechanism and addressing security risks through entropy-derived circuit outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If SoC architectures with multiple chiplets are used to increase design flexibility and overcome Moore's law limits, then design versatility and manufacturing yield are improved, but security vulnerability increases due to susceptibility to die swapping, interface tampering, and man-in-the-middle attacks
Solution Approach 1:
The patent implements preliminary authentication actions by measuring signal propagation delays between chiplets before establishing trusted communication channels. Delay-based PUFs are used to create unique cryptographic identities for each chiplet interconnect, enabling pre-verification of physical connections and preventing die swapping attacks before they can compromise system security
Solution Approach 2:
The patent introduces delay-based PUF measurements as an intermediary authentication mechanism between chiplets. This intermediary layer verifies the physical integrity of interconnects by measuring unique propagation delays, acting as a mediator that establishes trust without requiring direct physical inspection or complex cryptographic key exchange between chiplet manufacturers
2Reliability
If delay-based PUFs are implemented to verify system integrity and authenticate chiplets, then security reliability is improved, but measurement precision requirements increase due to the need to detect unique signal propagation delays
Solution Approach 1:
The patent employs self-service mechanisms where each chiplet autonomously measures and stores its own delay-based PUF characteristics during manufacturing or initialization. This self-characterization approach eliminates the need for highly precise external measurement equipment, as each chiplet serves as its own reference for measuring propagation delays through its unique physical interconnects
Solution Approach 2:
The patent transforms the measurement problem by changing parameters from absolute delay values to relative delay differences. By measuring time differences of arrival (TDOA) of signals between multiple channels and comparing relative delays rather than absolute timestamps, the system achieves sufficient precision using standard timing circuits without requiring ultra-precise measurement equipment
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The delay-based PUFs offer a low-cost, effective solution for verifying system integrity and authentication between chiplets, mitigating security threats by utilizing manufacturing variations to create unique signatures resistant to noise and tampering, ensuring secure communication in multi-die systems.
Implementation Method 1
A first signature based on characteristics of the transmitted signal may be measured at a first time, which constitutes the first evaluation of the PUF. The first signature may be based on an initial time measurement of the signal transmitted between the first chiplet and the second chiplet.
Data Source
AI summary
Embodiments described herein include a system, apparatus, article of manufacture, method and/or computer program product embodiments, and/or combinations and sub-combinations thereof, for delay-based physical unclonable functions (PUFs) for chiplets to verify system integrity. A die may include a plurality of chiplets including a first chiplet and a second chiplet. The first chiplet may be connected to the second chiplet via an interposer. As part of an authentication process, the first chiplet may request the second chiplet to transmit a signal via one or more wires of the interposer. A first signature based on the characteristics of the transmitted signal may be measured at a first time, which constitutes the first evaluation of the PUF. The first signature may be used as a baseline comparison for subsequent signatures as a means to confirm that the chiplets, interposers, and/or interconnects have not been altered or modified.