PUF Bit Reconstruction Using Stored Preliminary Error Correction
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Solution Overview
Problem
Current PUF generation methods in electronic devices, such as chip cards, face challenges in achieving consistent bit sequences under varying ambient conditions, leading to high error rates and increased hardware complexity and costs for error correction, which complicates the reconstruction of true PUF values from potentially erroneous ones.
Innovation Solution
A method involving a preliminary correction using a stored error vector (Deltat-1) to generate a preliminarily corrected PUF value (Bt), followed by error correction using an ECC algorithm to reconstruct the true PUF value (A), where the error vector (et) is updated and stored for subsequent corrections, leveraging the dependency of PUF generation on ambient conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard error correction methods are used to correct PUF bit sequences under varying ambient conditions, then the reliability of PUF reconstruction is improved, but the device complexity and computational overhead increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction vectors during a calibration phase under multiple ambient conditions. These correction vectors are computed in advance and stored in a lookup table, so that during actual PUF reconstruction, only a simple vector addition is needed instead of running complex error correction algorithms. This resolves the contradiction by shifting the computational complexity from the operational phase to the initial calibration phase.
Solution Approach 2:
The patent creates simplified copies of the error correction functionality in the form of pre-computed correction vectors. Instead of implementing full error correction algorithms during operation, the system uses stored correction vectors that replicate the essential corrective function. This copying approach reduces the hardware complexity during PUF reconstruction while maintaining reconstruction reliability.
2Measurement precision
If complex error correction algorithms are implemented to handle high error rates in PUF generation, then the accuracy of PUF reconstruction is improved, but the processing time and computational resources increase
Solution Approach 1:
The patent performs error correction in advance by computing correction vectors during a calibration phase and storing them for later use. During actual PUF reconstruction, the system simply adds the stored correction vector to the newly generated PUF bit sequence, which is a much faster operation than running complex error correction algorithms. This preliminary action resolves the contradiction by eliminating time-consuming computations during the critical reconstruction phase.
Solution Approach 2:
The patent prepares correction vectors in advance that cushion against expected errors under various ambient conditions. By anticipating and pre-computing the necessary corrections for different environmental scenarios, the system avoids the need for time-consuming error correction during actual PUF reconstruction, thus maintaining both accuracy and speed.
3Reliability
If PUF generation is performed multiple times to compensate for ambient condition variations, then the reliability of the true PUF value is improved, but the loss of time and increased processing overhead worsen
Solution Approach 1:
The patent performs multiple PUF generations and error analysis during an initial calibration phase to compute accurate correction vectors. These correction vectors capture the effects of ambient condition variations. During subsequent PUF reconstructions, the system only needs to generate one PUF value and add the pre-computed correction vector, avoiding the need to perform multiple generations each time. This resolves the contradiction by consolidating the time-consuming multiple generations into a one-time calibration process.
Data Source
AI summary
A method for reconstructing a physically uncloneable function (PUF) A for use in an electronic device is provided. The method includes generating a potentially erroneous PUF At and performing a preliminary correction of the potentially erroneous PUF At by means of a stored correction vector Deltat-1, to obtain a preliminarily corrected PUF Bt. The PUF A is reconstructed from the preliminarily corrected PUF Bt by means of an error correction algorithm. A corresponding apparatus is also provided.