Extracting Physically Unclonable Function From Spin Transfer Switching Characteristics in Magnetic Tunnel Junctions

Hardware security devices that include physically unclonable function (PUF) hold significant advantages over software-based secure identification and key storage. We propose a PUF for magnetic tunnel junctions (MTJs) and a method for extracting PUF based on intrinsic properties of spin transfer switching (STS). The STS characteristics of MTJs with perpendicular layers were measured and analyzed to determine how to extract PUF properties. Given the experimental intrinsic stochastic properties combined with the proposed sequence, we discuss the PUF properties extracted from MTJs. To realize secure hardware key in non-volatile devices, our methods and results are promising for constructing MTJ-PUF based on spintronic LSI devices.