Temporal Dynamics Makes Memristive Physical Unclonable Functions More Secure and Ultra‐Lightweight

Abstract Memristive physical unclonable function (PUF) is a recent entry to the list of security primitives, employing the intrinsic randomness of memristors. Although this represents a huge opportunity for memristors, all present memristive PUFs suffer from the problem of being device intensive because their entropies come exclusively from the spatial dimension. Here, a temporal PUF (TPUF) is reported, using the randomness of temporal dynamics of memristors as an entropy source. By exploiting temporal complexity, significant reduction of hardware overhead is achieved in the TPUF, from otherwise at least hundreds‐of‐memristors‐scale crossbar arrays to only a pair of memristors. This efficient and cheap TPUF can generate more than 1037 64‐bit challenge–response pairs (CRPs), whose number is infinitely up‐scalable (in principle) without hardware resource restrictions. Experiments have demonstrated that the TPUF has nearly ideal uniformity, diffuseness, uniqueness, low bit error rate, and NIST‐standard‐quality randomness. In addition, its hard‐to‐learn CRP relationship, forbiddingly large number of CRPs, and the potential slow‐down of the read‐out process make it highly resistant to machine learning attacks. This work represents a new opportunity for memristors for encryption.