DAGER: Exact Gradient Inversion for Large Language Models


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Date

2024

Publication Type

Conference Paper

ETH Bibliography

yes

Citations

Altmetric

Data

Abstract

Federated learning works by aggregating locally computed gradients from multiple clients, thus enabling collaborative training without sharing private client data. However, prior work has shown that the data can actually be recovered by the server using so-called gradient inversion attacks. While these attacks perform well when applied on images, they are limited in the text domain and only permit approximate reconstruction of small batches and short input sequences. In this work, we propose DAGER, the first algorithm to recover whole batches of input text exactly. DAGER leverages the low-rank structure of self-attention layer gradients and the discrete nature of token embeddings to efficiently check if a given token sequence is part of the client data. We use this check to exactly recover full batches in the honest-but-curious setting without any prior on the data for both encoder- and decoder-based architectures using exhaustive heuristic search and a greedy approach, respectively. We provide an efficient GPU implementation of DAGER and show experimentally that it recovers full batches of size up to 128 on large language models (LLMs), beating prior attacks in speed (20x at same batch size), scalability (10x larger batches), and reconstruction quality (ROUGE-1/2 > 0.99).

Publication status

published

Book title

Advances in Neural Information Processing Systems 37

Journal / series

Volume

37

Pages / Article No.

87801 - 87830

Publisher

Curran

Event

38th Conference on Neural Information Processing Systems (NeurIPS 2024)

Edition / version

Methods

Software

Geographic location

Date collected

Date created

Subject

Machine Learning (cs.LG); Distributed, Parallel, and Cluster Computing (cs.DC); FOS: Computer and information sciences; I.2.7; I.2.11

Organisational unit

03948 - Vechev, Martin / Vechev, Martin check_circle

Notes

Poster presented on December 12, 2024

Funding

101070617 - European Lighthouse on Secure and Safe AI (SBFI)

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