STT-MRAM-Based PUF Architecture Exploiting Magnetic Tunnel Junction Fabrication-Induced Variability

Abstract

Physically Unclonable Functions (PUFs) are emerging cryptographic primitives used to implement lowcost device authentication and secure secret key generation. Weak PUFs (i.e., devices able to generate a single signature or to deal with a limited number of challenges) are widely discussed in literature. One of the most investigated solutions today is based on SRAMs. However, the rapid development of low-power, high-density, high-performance SoCs has pushed the embedded memories to their limits and opened the field to the development of emerging memory technologies. The Spin-Transfer-Torque Magnetic Random Access Memory (STT-MRAM) has emerged as a promising choice for embedded memories due to its reduced read/write latency and high CMOS integration capability. In this article, we propose an innovative PUF design based on STT-MRAM memory. We exploit the high variability affecting the electrical resistance of the Magnetic Tunnel Junction (MTJ) device in anti-parallel magnetization. We will demonstrate that the proposed solution is robust, unclonable, and unpredictable.CCS Concepts: r Security and privacy → Hardware-based security protocols; r Hardware → Spintronics and magnetic technologiesAdditional Key Words and Phrases: Physically unclonable functions PUFs, STT-MRAM, emerging memory technology, security ACM Reference Format: . 2016. STT-MRAM-based PUF architecture exploiting magnetic tunnel junction fabrication-induced variability.

Practical Experiments to Evaluate Quality Metrics of MRAM-Based Physical Unclonable Functions

“…PUFs can be categorized into two classes: weak PUFs and strong PUFs [1,9]. Weak PUFs have one or few practical and valid inputs, the so-called challenge in literature [1,9].…”

“…PUFs can be categorized into two classes: weak PUFs and strong PUFs [1,9]. Weak PUFs have one or few practical and valid inputs, the so-called challenge in literature [1,9]. On the contrary, strong PUFs have a large number of challenges within a finite timeframe [1,9].…”

“…Weak PUFs have one or few practical and valid inputs, the so-called challenge in literature [1,9]. On the contrary, strong PUFs have a large number of challenges within a finite timeframe [1,9]. Weak PUFs employed within IoT devices have at least one unclonable output, the so-called response, which is unique per each fabricated device (PUF instance) while applying an identical challenge [2][3].…”

“…Different PUFs based on different MRAM types have been studied and proposed [9][10][11][12]. However, most of the studied MRAM-based PUFs have been conducted on simulation environments.…”

A Ring Oscillator-Based Identification Mechanism Immune to Aging and External Working Conditions

“…Therefore, PUFs are suitable to be the digital identity of devices on which they are embedded. So far, a significant number of PUF architectures has been introduced, covering delay-based PUFs (Arbiter [1], Ring Oscillator [2], Anderson [3], CNN-based [4]), which use pairs of symmetric paths for a digital contest to establish the output, and memory-based PUFs (SRAM [5], Butterfly [6], STT-MRAM [7]), which exploit the random initial pattern of a memory cell when being powered up.…”