Physically Unclonable Function With Dynamic Path Selection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional physically unclonable function (PUF) systems are vulnerable to side-channel attacks, such as optical emissions and power analysis, which can compromise the unpredictability and security of their responses.

Innovation Solution

A PUF system with multiple selectable paths and error correction logic is implemented, where an externally generated challenge randomly selects an internal challenge, ensuring a consistent corrected response through error correction and redundant bits, thereby enhancing resistance to side-channel attacks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional PUF systems use a single fixed path for challenge-response, then the response is predictable under repeated challenges, but the system structure is simple

Engineering Contradiction:

Improvepredictability of PUF responseVSAvoidPUF system structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic path selection by introducing a path selection module that randomly selects different internal challenge paths for each external challenge. This dynamic behavior ensures that even when the same external challenge is repeated, the system traverses different internal paths, making the response unpredictable to attackers while maintaining system security.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent divides the single PUF path into multiple selectable internal paths (first internal challenge path, second internal challenge path, etc.). Each path can be independently selected based on the challenge, creating segmented response channels that prevent attackers from predicting the response through repeated challenges on a single path.

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If multiple selectable paths are introduced to resist side-channel attacks, then security against attacks is improved, but the device complexity increases

Engineering Contradiction:

Improveresistance to side-channel attacksVSAvoidPUF system structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The path selection module introduces dynamic randomness into the system by selecting different internal paths for each challenge. This dynamic behavior confounds side-channel attacks because the physical characteristics (power consumption, electromagnetic emissions) vary across different paths, making it impossible for attackers to correlate measurements with specific secret values through repeated measurements.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent creates a composite PUF system that combines multiple internal paths with different physical characteristics. By composing these diverse paths into a unified system with random selection, the patent achieves enhanced security against side-channel attacks while managing complexity through a modular architecture.

Inventive Principle:

Principle #40Composite materials

3Stability of the object's composition

If error correction logic and redundant bits are added to ensure consistent corrected response, then response consistency is improved, but the device complexity increases

Engineering Contradiction:

Improveconsistency of PUF responseVSAvoiderror correction logic

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent incorporates error correction logic and redundant bits in advance to compensate for potential variations in PUF responses. This beforehand cushioning ensures that even when different internal paths produce slightly different raw responses due to manufacturing variations or environmental factors, the error correction logic can restore the original challenge value, maintaining response consistency and reliability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Loss of information

If random path selection is implemented for each challenge, then unpredictability against attackers is improved, but the difficulty of detecting and measuring increases

Engineering Contradiction:

Improveunpredictability of PUF outputVSAvoidPUF internal state

Core Design Contradiction:

Loss of informationVSDifficulty of detecting and measuring

Solution Approach 1:

The random path selection creates a dynamic system where the internal state traversal changes with each challenge. This makes it extremely difficult for attackers to detect and measure the internal PUF state because the same challenge can lead to different internal paths at different times, preventing attackers from building a consistent model of the internal state for analysis.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10797891B2Physically unclonable function resistant to side-channel attack and method therefor

Publication Date: 2020.10.06 NXP BV

AI summary

A physically unclonable function (PUF) system is provided. The PUF system includes an entropy source, a plurality of selectable paths, a random selection block, and error correction logic. The plurality of selectable paths are formed between the entropy source and an output for providing a PUF response. The random selection block is for randomly selecting one of the plurality of selectable paths in response to receiving a challenge. The error correction logic is coupled to the output for receiving the PUF response and for correcting any errors in the PUF response for the plurality of selectable paths. By using a different path through the entropy source each time a challenge is received, protection is provided against side-channel attacks.