Graduate Exam Abstract

Abstract: Non-volatile flash memories, the fundamental building blocks of solid-state storage devices, provide compact, high-capacity, high-speed, and low-power storage solutions across a wide range of computing systems, including consumer electronics, automotive, military, industrial, healthcare, and enterprise applications. The global flash memory market currently exceeds $60 billion and is projected to surpass $80 billion by 2030. However, deleting data instantly from flash memory is not always straightforward, as it can incur significant overhead and accelerate device wear. A recent report found that 42% of used SSDs sold on eBay contained recoverable sensitive data. While standard deletion methods render data inaccessible to users, our research shows that it can often be partially or fully recovered through physical characterization, emphasizing the urgent need for techniques that ensure prompt, permanent, and irreversible data removal.

This dissertation addresses this challenge by focusing on innovative data sanitization techniques for 3D NAND flash technology. We analyze, for the first time, the feasibility of overwrite-based instant sanitization in 3D NAND flash memories and show that it can cause significant disturbance to valid data. To address this, we propose a PULSE solution that mitigates overwrite-induced disturbances. Additionally, we investigate the potential for data leakage even after block erase operations, traditionally considered the most secure sanitization method in flash storage. Our findings highlight a critical gap in current practices: logical erase and overwrite protocols alone are insufficient for secure data removal. We suggest that future research should explore adaptive refresh policies, hardware-assisted secure erase commands, and the standardization of sanitization guidelines to ensure truly secure flash memory storage.

Adviser: Biswajit Ray
Co-Adviser: N/A
Non-ECE Member: Indrajit Ray
Member 3: Sudeep Pasricha
Addional Members: Jie Rockey Luo

Publications:
https://scholar.google.com/citations?view_op=list_works&hl=en&user=tnPZq1YAAAAJ

Program of Study:
ECE544
ECE799
ECE799
ECE799
ECE799
ECE799
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