Characterization of ReRAM Arrays Operating in the Pre-formed Range to Design Reliable PUFs

Pre-formed Resistive Random Access Memory arrays are analyzed for the purpose of designing Physical Unclonable Functions to enhance the tamper resistance of Internet of Things devices. The evaluation includes subjecting these pre-formed arrays to repeated read operations and varying operating temperature ranges to assess their impacts on reliability. Additionally, a Ternary Addressable Public Key Infrastructure protocol is employed to generate 256-bit long keys, with error rates evaluated by comparing keys generated by the server database and client devices. To improve the bit error rate performance, fuzzy zones are implemented to mask unstable cells positioned too close to the binary threshold, and the furthermost cells from the threshold in a trit stream are selected to produce robust keys. This method accounts for inherent cycle-to-cycle variation and temperature drifts, ensuring high reproducibility. Experimental results demonstrate that the design achieves bit error rates as low as 10^-8 in 256-bit long keys, averaged over one million cycles.