Highly Independent MTJ-Based PUF System Using Diode-Connected Transistor and Two-Step Postprocessing for Improved Response Stability

Sehee Lim, Byungkyu Song, Seong Ook Jung

Research output: Contribution to journalArticle

Abstract

In physically unclonable functions (PUFs), generating random cryptographs is required to secure private information. Various memory-based PUFs (MemPUFs), where cryptographs are generated independently from each PUF cell to increase the unpredictability of the cryptographs, have been proposed. Among them, the spin-transfer torque magnetic random-access memory MemPUF generates constant responses under temperature and voltage variations by exploiting a magnetic tunnel junction (MTJ) as the variation source. However, its response stability is diminished by the different characteristics of the two access transistors used in a PUF cell. To solve this problem, a novel PUF array that employs a diode-connected transistor and a shared access transistor, is proposed. In addition, a two-step postprocessing is adopted: 1) a write-back technique that amplifies the initial mismatch of MTJ resistances, and 2) a cell-classification technique that detects unstable PUF cells and discards their responses. The Monte Carlo HSPICE simulation results using industry-compatible 65-nm technology show that the proposed PUF system achieves the highest independence (autocorrelation factor of 0.0306) and the lowest maximum bit error rate (BER) under temperature and supply-voltage variations (<0.01% and 0.04% in the ranges of -25 to 75 °C and 0.8-1.2 V, respectively) compared with conventional PUF systems that exploit independent variation sources.

Original languageEnglish
Article number9020171
Pages (from-to)2798-2807
Number of pages10
JournalIEEE Transactions on Information Forensics and Security
Volume15
DOIs
Publication statusPublished - 2020 Jan 1

All Science Journal Classification (ASJC) codes

  • Safety, Risk, Reliability and Quality
  • Computer Networks and Communications

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