Integrated Circuit Authentication via Physical Unclonable Functions
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Solution Overview
Problem
Existing authentication methods for integrated circuits are vulnerable to counterfeiting and invasive attacks, as adversaries can potentially measure and duplicate the secret keys embedded in chips using invasive and non-invasive methods.
Innovation Solution
Designing integrated circuit chips with a large set of unique, measurable physical characteristics that are difficult to duplicate, allowing for authentication by selectively measuring a subset of these characteristics and comparing them to pre-stored measurements, making it impractical for adversaries to exhaustively measure all characteristics or create a model of the chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a secret key is embedded in a chip for authentication, then authentication capability is improved, but vulnerability to invasive attacks increases
Solution Approach 1:
The patent extracts the secret key from being a separate storable entity and instead embeds it directly into the physical structure of the chip through fabrication process variations. The key is no longer something that can be read out or extracted, but is embodied in the unique physical characteristics of the chip itself, such as threshold voltages of transistors or other measurable physical properties that differ between chips due to manufacturing variations.
Solution Approach 2:
The patent introduces an intermediary measurement and comparison system that authenticates the chip by measuring its unique physical characteristics and comparing them against stored reference values. This intermediary process allows authentication without directly exposing or reading the secret key, thereby protecting it from invasive attacks while maintaining reliable authentication capability.
2Reliability
If sensing circuitry is added to detect intrusion and erase sensitive information, then security against physical invasion is improved, but device complexity increases
Solution Approach 1:
The patent merges the authentication function with the existing chip structure by utilizing the chip's inherent physical characteristics for identification. Rather than adding separate sensing circuitry and erasure mechanisms, the authentication system is integrated into the chip's fabrication process itself, where the unique physical properties serve as both the identifier and the security mechanism, eliminating the need for additional protective components.
3Reliability
If a large set of measurable physical characteristics is used for authentication, then resistance to counterfeiting is improved, but measurement and comparison complexity increases
Solution Approach 1:
The patent applies partial action by selecting and measuring only a specific subset of physical characteristics that are sufficient for authentication, rather than measuring all possible physical properties of the chip. This selective measurement approach maintains strong resistance to counterfeiting while keeping the measurement and comparison system manageable in complexity.
Data Source
AI summary
A group of devices are fabricated based on a common design, each device having a corresponding plurality of measurable characteristics that is unique in the group to that device, each device having a measurement module for measuring the measurable characteristics. Authentication of one of the group of devices is enabled by selective measurement of one or more of the plurality of measurable characteristics of the device.