PUF-Based Global Identity Sharing for Tamper Resistance
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Solution Overview
Problem
Existing approaches to constructing a device's identity based on hardware intrinsic properties do not effectively prevent adversaries from systematically extracting shares, leading to vulnerabilities in tamper resistance, especially when multiple devices are involved.
Innovation Solution
Implementing a system where multiple PUF-enabled devices jointly perform cryptographic operations using a shared global identity, with each device having at least two shares, and requiring a threshold number of devices to successfully compute operations, thereby mitigating adversarial tampering attacks by limiting share exposure and using threshold operations to secure the global identity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple devices share a global identity with threshold operations, then system-wide tamper resistance is improved, but device complexity increases
Solution Approach 1:
The global identity is segmented into multiple shares distributed across different devices. Each device holds a portion of the secret rather than the complete secret, so that compromising one device does not reveal the entire identity. The secret is divided such that a threshold number of shares are required to reconstruct it, implementing security through distribution.
Solution Approach 2:
The system dynamically adjusts the threshold parameter based on the number of participating devices. As devices join or leave the system, the threshold requirement is recalculated and updated, allowing the security parameters to adapt to the current system state without requiring complete system reconfiguration.
2Object-affected harmful factors
If shares are distributed across multiple devices, then extraction resistance is improved, but the risk of systematic extraction attacks increases
Solution Approach 1:
The system requires more shares to be collected than the minimum threshold needed for reconstruction. By setting the threshold lower than the total number of devices holding shares, the system creates an excess security margin that prevents adversaries from successfully extracting enough shares even if they compromise multiple devices, as they would need to compromise more devices than necessary.
3Reliability
If threshold operations are implemented on multiple shares, then cryptographic security is improved, but computational overhead increases
Solution Approach 1:
The patent extracts and removes the secret from memory before cryptographic operations are performed. Instead of keeping the secret in memory during computation, the system retrieves only the necessary shares, performs the threshold operation to compute the result, and then discards the shares. This extraction approach minimizes the time and energy the secret spends in vulnerable states.
4Adaptability or versatility
If shares are refreshed dynamically, then adaptability to participant changes is improved, but system operation complexity increases
Solution Approach 1:
The system dynamically adjusts the threshold parameter based on the number of participating devices. As devices join or leave the system, the threshold requirement is recalculated and updated, allowing the security parameters to adapt to the current system state without requiring complete system reconfiguration.
Solution Approach 2:
The threshold parameter is changed adaptively based on system conditions. When the number of participating devices changes, the threshold is recalibrated to maintain appropriate security levels, and this parameter change is propagated through the system to update operational requirements.
Data Source
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AI summary
Various embodiments enhance security and tamper resistance of device or components having a hardware intrinsic identity. For example, devices or components having PUFs can map challenges and helper values to a secret or share of secret to utilize a local identity in cryptographic operations. A plurality of components having individual identities can be extend so that the plurality of components can enroll into a shared global identity. Shares of the global identity can be distributed among the plurality of components or devices such that at least two devices must provide at least two shares of the global identity (or threshold operations on the at least two shares) to successfully use the global identity. Such sharing mitigates adversarial tampering attack on the global identity. Share refresh protocols can provide additional security, enable introduction of new components or devices to the global identity, and allow removal of existing components or devices.