Attacks on Approximate Caches in Text-to-Image Diffusion Models

Fuente: arXiv
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Autori principali: Sun, Desen, Jie, Shuncheng, Liu, Sihang
Natura: Preprint
Pubblicazione: 2025
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author Sun, Desen
Jie, Shuncheng
Liu, Sihang
author_facet Sun, Desen
Jie, Shuncheng
Liu, Sihang
contents Diffusion models are a powerful class of generative models that produce images and other content from user prompts, but they are computationally intensive. To mitigate this cost, recent academic and industry work has adopted approximate caching, which reuses intermediate states from similar prompts in a cache. While efficient, this optimization introduces new security risks by breaking isolation among users. This paper provides a comprehensive assessment of the security vulnerabilities introduced by approximate caching. First, we demonstrate a remote covert channel established with the approximate cache, where a sender injects prompts with special keywords into the cache system and a receiver can recover that even after days, to exchange information. Second, we introduce a prompt stealing attack using the approximate cache, where an attacker can recover existing cached prompts from hits. Finally, we introduce a poisoning attack that embeds the attacker's logos into the previously stolen prompt, leading to unexpected logo rendering for the requests that hit the poisoned cache prompts. These attacks are all performed remotely through the serving system, demonstrating severe security vulnerabilities in approximate caching. The code for this work is available.
format Preprint
id arxiv_https___arxiv_org_abs_2508_20424
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Attacks on Approximate Caches in Text-to-Image Diffusion Models
Sun, Desen
Jie, Shuncheng
Liu, Sihang
Cryptography and Security
Diffusion models are a powerful class of generative models that produce images and other content from user prompts, but they are computationally intensive. To mitigate this cost, recent academic and industry work has adopted approximate caching, which reuses intermediate states from similar prompts in a cache. While efficient, this optimization introduces new security risks by breaking isolation among users. This paper provides a comprehensive assessment of the security vulnerabilities introduced by approximate caching. First, we demonstrate a remote covert channel established with the approximate cache, where a sender injects prompts with special keywords into the cache system and a receiver can recover that even after days, to exchange information. Second, we introduce a prompt stealing attack using the approximate cache, where an attacker can recover existing cached prompts from hits. Finally, we introduce a poisoning attack that embeds the attacker's logos into the previously stolen prompt, leading to unexpected logo rendering for the requests that hit the poisoned cache prompts. These attacks are all performed remotely through the serving system, demonstrating severe security vulnerabilities in approximate caching. The code for this work is available.
title Attacks on Approximate Caches in Text-to-Image Diffusion Models
topic Cryptography and Security
url https://arxiv.org/abs/2508.20424