Private Counterfactual Retrieval

Fuente: arXiv
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Main Authors: Nomeir, Mohamed, Dissanayake, Pasan, Meel, Shreya, Dutta, Sanghamitra, Ulukus, Sennur
Format: Preprint
Published: 2024
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author Nomeir, Mohamed
Dissanayake, Pasan
Meel, Shreya
Dutta, Sanghamitra
Ulukus, Sennur
author_facet Nomeir, Mohamed
Dissanayake, Pasan
Meel, Shreya
Dutta, Sanghamitra
Ulukus, Sennur
contents Transparency and explainability are two extremely important aspects to be considered when employing black-box machine learning models in high-stake applications. Providing counterfactual explanations is one way of fulfilling this requirement. However, this also poses a threat to the privacy of both the institution that is providing the explanation as well as the user who is requesting it. In this work, we propose multiple schemes inspired by private information retrieval (PIR) techniques which ensure the \emph{user's privacy} when retrieving counterfactual explanations. We present a scheme which retrieves the \emph{exact} nearest neighbor counterfactual explanation from a database of accepted points while achieving perfect (information-theoretic) privacy for the user. While the scheme achieves perfect privacy for the user, some leakage on the database is inevitable which we quantify using a mutual information based metric. Furthermore, we propose strategies to reduce this leakage to achieve an advanced degree of database privacy. We extend these schemes to incorporate user's preference on transforming their attributes, so that a more actionable explanation can be received. Since our schemes rely on finite field arithmetic, we empirically validate our schemes on real datasets to understand the trade-off between the accuracy and the finite field sizes. Finally, we present numerical results to support our theoretical findings, and compare the database leakage of the proposed schemes.
format Preprint
id arxiv_https___arxiv_org_abs_2410_13812
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Private Counterfactual Retrieval
Nomeir, Mohamed
Dissanayake, Pasan
Meel, Shreya
Dutta, Sanghamitra
Ulukus, Sennur
Information Theory
Cryptography and Security
Machine Learning
Signal Processing
Transparency and explainability are two extremely important aspects to be considered when employing black-box machine learning models in high-stake applications. Providing counterfactual explanations is one way of fulfilling this requirement. However, this also poses a threat to the privacy of both the institution that is providing the explanation as well as the user who is requesting it. In this work, we propose multiple schemes inspired by private information retrieval (PIR) techniques which ensure the \emph{user's privacy} when retrieving counterfactual explanations. We present a scheme which retrieves the \emph{exact} nearest neighbor counterfactual explanation from a database of accepted points while achieving perfect (information-theoretic) privacy for the user. While the scheme achieves perfect privacy for the user, some leakage on the database is inevitable which we quantify using a mutual information based metric. Furthermore, we propose strategies to reduce this leakage to achieve an advanced degree of database privacy. We extend these schemes to incorporate user's preference on transforming their attributes, so that a more actionable explanation can be received. Since our schemes rely on finite field arithmetic, we empirically validate our schemes on real datasets to understand the trade-off between the accuracy and the finite field sizes. Finally, we present numerical results to support our theoretical findings, and compare the database leakage of the proposed schemes.
title Private Counterfactual Retrieval
topic Information Theory
Cryptography and Security
Machine Learning
Signal Processing
url https://arxiv.org/abs/2410.13812