Search Results for author: Saeed Mahloujifar

Found 36 papers, 12 papers with code

Guarantees of confidentiality via Hammersley-Chapman-Robbins bounds

1 code implementation3 Apr 2024 Kamalika Chaudhuri, Chuan Guo, Laurens van der Maaten, Saeed Mahloujifar, Mark Tygert

The HCR bounds appear to be insufficient on their own to guarantee confidentiality of the inputs to inference with standard deep neural nets, "ResNet-18" and "Swin-T," pre-trained on the data set, "ImageNet-1000," which contains 1000 classes.

Image Classification

Privacy Amplification for the Gaussian Mechanism via Bounded Support

no code implementations7 Mar 2024 Shengyuan Hu, Saeed Mahloujifar, Virginia Smith, Kamalika Chaudhuri, Chuan Guo

Data-dependent privacy accounting frameworks such as per-instance differential privacy (pDP) and Fisher information loss (FIL) confer fine-grained privacy guarantees for individuals in a fixed training dataset.

Private Fine-tuning of Large Language Models with Zeroth-order Optimization

no code implementations9 Jan 2024 Xinyu Tang, Ashwinee Panda, Milad Nasr, Saeed Mahloujifar, Prateek Mittal

We introduce DP-ZO, a new method for fine-tuning large language models that preserves the privacy of training data by privatizing zeroth-order optimization.

Privacy Preserving

Publicly Detectable Watermarking for Language Models

no code implementations27 Oct 2023 Jaiden Fairoze, Sanjam Garg, Somesh Jha, Saeed Mahloujifar, Mohammad Mahmoody, Mingyuan Wang

We construct the first provable watermarking scheme for language models with public detectability or verifiability: we use a private key for watermarking and a public key for watermark detection.

A Randomized Approach for Tight Privacy Accounting

no code implementations17 Apr 2023 Jiachen T. Wang, Saeed Mahloujifar, Tong Wu, Ruoxi Jia, Prateek Mittal

In this paper, we propose a new differential privacy paradigm called estimate-verify-release (EVR), which addresses the challenges of providing a strict upper bound for privacy parameter in DP compositions by converting an estimate of privacy parameter into a formal guarantee.

Privacy Preserving

MultiRobustBench: Benchmarking Robustness Against Multiple Attacks

no code implementations21 Feb 2023 Sihui Dai, Saeed Mahloujifar, Chong Xiang, Vikash Sehwag, Pin-Yu Chen, Prateek Mittal

Using our framework, we present the first leaderboard, MultiRobustBench, for benchmarking multiattack evaluation which captures performance across attack types and attack strengths.

Benchmarking

Revisiting the Assumption of Latent Separability for Backdoor Defenses

1 code implementation ICLR 2023 Xiangyu Qi, Tinghao Xie, Tinghao_Xie1, Yiming Li, Saeed Mahloujifar, Prateek Mittal

This latent separation is so pervasive that a family of backdoor defenses directly take it as a default assumption (dubbed latent separability assumption), based on which to identify poison samples via cluster analysis in the latent space.

Uncovering Adversarial Risks of Test-Time Adaptation

no code implementations29 Jan 2023 Tong Wu, Feiran Jia, Xiangyu Qi, Jiachen T. Wang, Vikash Sehwag, Saeed Mahloujifar, Prateek Mittal

Recently, test-time adaptation (TTA) has been proposed as a promising solution for addressing distribution shifts.

Test-time Adaptation

DP-RAFT: A Differentially Private Recipe for Accelerated Fine-Tuning

no code implementations8 Dec 2022 Ashwinee Panda, Xinyu Tang, Vikash Sehwag, Saeed Mahloujifar, Prateek Mittal

A major direction in differentially private machine learning is differentially private fine-tuning: pretraining a model on a source of "public data" and transferring the extracted features to downstream tasks.

Image Classification

Renyi Differential Privacy of Propose-Test-Release and Applications to Private and Robust Machine Learning

no code implementations16 Sep 2022 Jiachen T. Wang, Saeed Mahloujifar, Shouda Wang, Ruoxi Jia, Prateek Mittal

As an application of our analysis, we show that PTR and our theoretical results can be used to design differentially private variants for byzantine robust training algorithms that use robust statistics for gradients aggregation.

Overparameterization from Computational Constraints

no code implementations27 Aug 2022 Sanjam Garg, Somesh Jha, Saeed Mahloujifar, Mohammad Mahmoody, Mingyuan Wang

In particular, for computationally bounded learners, we extend the recent result of Bubeck and Sellke [NeurIPS'2021] which shows that robust models might need more parameters, to the computational regime and show that bounded learners could provably need an even larger number of parameters.

Just Rotate it: Deploying Backdoor Attacks via Rotation Transformation

no code implementations22 Jul 2022 Tong Wu, Tianhao Wang, Vikash Sehwag, Saeed Mahloujifar, Prateek Mittal

Our attack can be easily deployed in the real world since it only requires rotating the object, as we show in both image classification and object detection applications.

Data Augmentation Image Classification +3

Towards A Proactive ML Approach for Detecting Backdoor Poison Samples

2 code implementations26 May 2022 Xiangyu Qi, Tinghao Xie, Jiachen T. Wang, Tong Wu, Saeed Mahloujifar, Prateek Mittal

First, we uncover a post-hoc workflow underlying most prior work, where defenders passively allow the attack to proceed and then leverage the characteristics of the post-attacked model to uncover poison samples.

Circumventing Backdoor Defenses That Are Based on Latent Separability

1 code implementation26 May 2022 Xiangyu Qi, Tinghao Xie, Yiming Li, Saeed Mahloujifar, Prateek Mittal

This latent separation is so pervasive that a family of backdoor defenses directly take it as a default assumption (dubbed latent separability assumption), based on which to identify poison samples via cluster analysis in the latent space.

Formulating Robustness Against Unforeseen Attacks

1 code implementation28 Apr 2022 Sihui Dai, Saeed Mahloujifar, Prateek Mittal

Based on our generalization bound, we propose variation regularization (VR) which reduces variation of the feature extractor across the source threat model during training.

Optimal Membership Inference Bounds for Adaptive Composition of Sampled Gaussian Mechanisms

no code implementations12 Apr 2022 Saeed Mahloujifar, Alexandre Sablayrolles, Graham Cormode, Somesh Jha

A common countermeasure against MI attacks is to utilize differential privacy (DP) during model training to mask the presence of individual examples.

ObjectSeeker: Certifiably Robust Object Detection against Patch Hiding Attacks via Patch-agnostic Masking

1 code implementation3 Feb 2022 Chong Xiang, Alexander Valtchanov, Saeed Mahloujifar, Prateek Mittal

An attacker can use a single physically-realizable adversarial patch to make the object detector miss the detection of victim objects and undermine the functionality of object detection applications.

Autonomous Vehicles Object +2

SparseFed: Mitigating Model Poisoning Attacks in Federated Learning with Sparsification

1 code implementation12 Dec 2021 Ashwinee Panda, Saeed Mahloujifar, Arjun N. Bhagoji, Supriyo Chakraborty, Prateek Mittal

Federated learning is inherently vulnerable to model poisoning attacks because its decentralized nature allows attackers to participate with compromised devices.

Federated Learning Model Poisoning

Mitigating Membership Inference Attacks by Self-Distillation Through a Novel Ensemble Architecture

no code implementations15 Oct 2021 Xinyu Tang, Saeed Mahloujifar, Liwei Song, Virat Shejwalkar, Milad Nasr, Amir Houmansadr, Prateek Mittal

The goal of this work is to train ML models that have high membership privacy while largely preserving their utility; we therefore aim for an empirical membership privacy guarantee as opposed to the provable privacy guarantees provided by techniques like differential privacy, as such techniques are shown to deteriorate model utility.

Privacy Preserving

Parameterizing Activation Functions for Adversarial Robustness

no code implementations11 Oct 2021 Sihui Dai, Saeed Mahloujifar, Prateek Mittal

To address this, we analyze the direct impact of activation shape on robustness through PAFs and observe that activation shapes with positive outputs on negative inputs and with high finite curvature can increase robustness.

Adversarial Robustness

PatchCleanser: Certifiably Robust Defense against Adversarial Patches for Any Image Classifier

1 code implementation20 Aug 2021 Chong Xiang, Saeed Mahloujifar, Prateek Mittal

Remarkably, PatchCleanser achieves 83. 9% top-1 clean accuracy and 62. 1% top-1 certified robust accuracy against a 2%-pixel square patch anywhere on the image for the 1000-class ImageNet dataset.

Image Classification

Membership Inference on Word Embedding and Beyond

no code implementations21 Jun 2021 Saeed Mahloujifar, Huseyin A. Inan, Melissa Chase, Esha Ghosh, Marcello Hasegawa

Indeed, our attack is a cheaper membership inference attack on text-generative models, which does not require the knowledge of the target model or any expensive training of text-generative models as shadow models.

Inference Attack Language Modelling +3

Property Inference From Poisoning

no code implementations26 Jan 2021 Melissa Chase, Esha Ghosh, Saeed Mahloujifar

In this work, we study property inference in scenarios where the adversary can maliciously control part of the training data (poisoning data) with the goal of increasing the leakage.

Data Poisoning

Model-Targeted Poisoning Attacks with Provable Convergence

1 code implementation30 Jun 2020 Fnu Suya, Saeed Mahloujifar, Anshuman Suri, David Evans, Yuan Tian

Our attack is the first model-targeted poisoning attack that provides provable convergence for convex models, and in our experiments, it either exceeds or matches state-of-the-art attacks in terms of attack success rate and distance to the target model.

Computational Concentration of Measure: Optimal Bounds, Reductions, and More

no code implementations11 Jul 2019 Omid Etesami, Saeed Mahloujifar, Mohammad Mahmoody

Product measures of dimension $n$ are known to be concentrated in Hamming distance: for any set $S$ in the product space of probability $\epsilon$, a random point in the space, with probability $1-\delta$, has a neighbor in $S$ that is different from the original point in only $O(\sqrt{n\ln(1/(\epsilon\delta))})$ coordinates.

Open-Ended Question Answering

Lower Bounds for Adversarially Robust PAC Learning

no code implementations13 Jun 2019 Dimitrios I. Diochnos, Saeed Mahloujifar, Mohammad Mahmoody

In this work, we initiate a formal study of probably approximately correct (PAC) learning under evasion attacks, where the adversary's goal is to \emph{misclassify} the adversarially perturbed sample point $\widetilde{x}$, i. e., $h(\widetilde{x})\neq c(\widetilde{x})$, where $c$ is the ground truth concept and $h$ is the learned hypothesis.

PAC learning

Empirically Measuring Concentration: Fundamental Limits on Intrinsic Robustness

1 code implementation NeurIPS 2019 Saeed Mahloujifar, Xiao Zhang, Mohammad Mahmoody, David Evans

Many recent works have shown that adversarial examples that fool classifiers can be found by minimally perturbing a normal input.

Image Classification

Adversarially Robust Learning Could Leverage Computational Hardness

no code implementations28 May 2019 Sanjam Garg, Somesh Jha, Saeed Mahloujifar, Mohammad Mahmoody

On the reverse directions, we also show that the existence of such learning task in which computational robustness beats information theoretic robustness requires computational hardness by implying (average-case) hardness of NP.

Adversarial Risk and Robustness: General Definitions and Implications for the Uniform Distribution

no code implementations NeurIPS 2018 Dimitrios I. Diochnos, Saeed Mahloujifar, Mohammad Mahmoody

We study both "inherent" bounds that apply to any problem and any classifier for such a problem as well as bounds that apply to specific problems and specific hypothesis classes.

Can Adversarially Robust Learning Leverage Computational Hardness?

no code implementations2 Oct 2018 Saeed Mahloujifar, Mohammad Mahmoody

Making learners robust to adversarial perturbation at test time (i. e., evasion attacks) or training time (i. e., poisoning attacks) has emerged as a challenging task.

Universal Multi-Party Poisoning Attacks

no code implementations10 Sep 2018 Saeed Mahloujifar, Mohammad Mahmoody, Ameer Mohammed

In this work, we demonstrate universal multi-party poisoning attacks that adapt and apply to any multi-party learning process with arbitrary interaction pattern between the parties.

The Curse of Concentration in Robust Learning: Evasion and Poisoning Attacks from Concentration of Measure

no code implementations9 Sep 2018 Saeed Mahloujifar, Dimitrios I. Diochnos, Mohammad Mahmoody

We show that if the metric probability space of the test instance is concentrated, any classifier with some initial constant error is inherently vulnerable to adversarial perturbations.

Learning under $p$-Tampering Attacks

no code implementations10 Nov 2017 Saeed Mahloujifar, Dimitrios I. Diochnos, Mohammad Mahmoody

They obtained $p$-tampering attacks that increase the error probability in the so called targeted poisoning model in which the adversary's goal is to increase the loss of the trained hypothesis over a particular test example.

PAC learning

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