An STT-MRAM based strong PUF

Physically Unclonable Functions (PUFs) are an emerging technology that could play the key roles in various security applications. Depending upon the size of its truth-table, i.e., the search space for an attacker to fully specify its behavior, a PUF can be categorized as either “weak” or “strong”. While weak PUFs have a limited search space, polynomial with respect to the number of their building components, strong PUFs offer a huge search space, making them more suitable for a wider range of security applications, such as device authentication and logic obfuscation. This paper presents a scheme for making a strong PUF based on Spin-Transfer Torque Magnetic RAM (STT-MRAM), an emerging nano-electronic memory device. To achieve an STT-MRAM based strong PUF with a huge search space, we proposed the idea of “group formation” to exploit the nano-scale analog disorders of STT-MRAM devices. Simulation results confirm the quality of the proposed strong PUF. In the end, this paper sheds light on how to make a strong PUF in general, by extending the idea of group formation beyond the STT-MRAM devices.