Researchers from Beihang University and Truth Memory Corporation have fabricated a 1 Kbit SOT-MRAM chip using a 180 nm complementary metal oxide semiconductor (CMOS) process, and implemented a physical unclonable function (PUF) on it. This research represents a significant step forward in the field of PUFs.
The newly developed SOT-MRAM sr-PUF achieves a strong, highly reliable, and reconfigurable PUF that can resist machine-learning attacks. The performance of the SOT-MRAM sr-PUF is remarkable - it has a challenge-response pair (CRP) capacity of 109. Its uniformity is 50.07%, diffuseness is 50%, uniqueness is 49.89%, and the bit error rate is 0%, even in a 375 K environment. These values are near-ideal, indicating excellent randomness and reliability.
Moreover, the reconfigurability of the PUF is a key feature. By applying different write voltages, the PUF can dynamically refresh its CRPs. The reconfigurable Hamming distance is 49.31%, and the correlation coefficient between different reconfiguration cycles is less than 0.2. This makes it difficult for attackers to extract output keys through side-channel analysis.
When it comes to machine-learning attacks, the SOT-MRAM sr-PUF shows great resilience. Tested with three machine-learning algorithms (logistic regression, support vector machine, and multilayer perceptron), its prediction accuracy is close to the ideal 50%, meaning it can effectively resist such attacks.
