A False Sense of Privacy: Evaluating Textual Data Sanitization Beyond Surface-level Privacy Leakage

Fuente: arXiv
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Main Authors: Xin, Rui, Mireshghallah, Niloofar, Li, Shuyue Stella, Duan, Michael, Kim, Hyunwoo, Choi, Yejin, Tsvetkov, Yulia, Oh, Sewoong, Koh, Pang Wei
Format: Preprint
Published: 2025
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author Xin, Rui
Mireshghallah, Niloofar
Li, Shuyue Stella
Duan, Michael
Kim, Hyunwoo
Choi, Yejin
Tsvetkov, Yulia
Oh, Sewoong
Koh, Pang Wei
author_facet Xin, Rui
Mireshghallah, Niloofar
Li, Shuyue Stella
Duan, Michael
Kim, Hyunwoo
Choi, Yejin
Tsvetkov, Yulia
Oh, Sewoong
Koh, Pang Wei
contents Sanitizing sensitive text data typically involves removing personally identifiable information (PII) or generating synthetic data under the assumption that these methods adequately protect privacy; however, their effectiveness is often only assessed by measuring the leakage of explicit identifiers but ignoring nuanced textual markers that can lead to re-identification. We challenge the above illusion of privacy by proposing a new framework that evaluates re-identification attacks to quantify individual privacy risks upon data release. Our approach shows that seemingly innocuous auxiliary information -- such as routine social activities -- can be used to infer sensitive attributes like age or substance use history from sanitized data. For instance, we demonstrate that Azure's commercial PII removal tool fails to protect 74\% of information in the MedQA dataset. Although differential privacy mitigates these risks to some extent, it significantly reduces the utility of the sanitized text for downstream tasks. Our findings indicate that current sanitization techniques offer a \textit{false sense of privacy}, highlighting the need for more robust methods that protect against semantic-level information leakage.
format Preprint
id arxiv_https___arxiv_org_abs_2504_21035
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A False Sense of Privacy: Evaluating Textual Data Sanitization Beyond Surface-level Privacy Leakage
Xin, Rui
Mireshghallah, Niloofar
Li, Shuyue Stella
Duan, Michael
Kim, Hyunwoo
Choi, Yejin
Tsvetkov, Yulia
Oh, Sewoong
Koh, Pang Wei
Cryptography and Security
Computation and Language
Machine Learning
Sanitizing sensitive text data typically involves removing personally identifiable information (PII) or generating synthetic data under the assumption that these methods adequately protect privacy; however, their effectiveness is often only assessed by measuring the leakage of explicit identifiers but ignoring nuanced textual markers that can lead to re-identification. We challenge the above illusion of privacy by proposing a new framework that evaluates re-identification attacks to quantify individual privacy risks upon data release. Our approach shows that seemingly innocuous auxiliary information -- such as routine social activities -- can be used to infer sensitive attributes like age or substance use history from sanitized data. For instance, we demonstrate that Azure's commercial PII removal tool fails to protect 74\% of information in the MedQA dataset. Although differential privacy mitigates these risks to some extent, it significantly reduces the utility of the sanitized text for downstream tasks. Our findings indicate that current sanitization techniques offer a \textit{false sense of privacy}, highlighting the need for more robust methods that protect against semantic-level information leakage.
title A False Sense of Privacy: Evaluating Textual Data Sanitization Beyond Surface-level Privacy Leakage
topic Cryptography and Security
Computation and Language
Machine Learning
url https://arxiv.org/abs/2504.21035