Biswajit Ray

Habib Ur Rahman, Tharini Suresh, Sudeep Pasricha et al.

This paper presents MCFlash, a practical and immediately deployable technique for executing bulk bitwise operations directly within commercial off-the-shelf(COTS) 3D NAND flash chips. MCFlash relies solely on standard user-mode instructions, combining Multi-Level Cell (MLC) data encodings with dynamically tuned read reference voltages to execute in-place bitwise operations. We evaluate MCFlash across diverse NAND flash chips, both floating-gate and charge-trap variants, from different generations. Our results represent the first demonstration of error-free, on-chip bitwise operations, sustaining over one billion operations on fresh blocks and maintaining bit-error rates below 0.015% even after 10,000 program/erase (P/E) cycles.

B. M. S. Bahar Talukder, Biswajit Ray, Domenic Forte et al.

Physically Unclonable Functions (PUFs) are potential security blocks to generate unique and more secure keys in low-cost cryptographic applications. Dynamic random-access memory (DRAM) has been proposed as one of the promising candidates for generating robust keys. Unfortunately, the existing techniques of generating device signatures from DRAM is very slow, destructive (destroy the current data), and disruptive to system operation. In this paper, we propose \textit{precharge} latency-based PUF (PreLatPUF) that exploits DRAM \textit{precharge} latency variations to generate signatures. The proposed PreLatPUF is fast, robust, least disruptive, and non-destructive. The silicon results from commercially available $DDR3$ chips from different manufacturers show that the proposed key generation technique is at least $ \sim 1,192X$ faster than the existing approaches, while reliably reproducing the key in extreme operating conditions.