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Related papers: A Low-Cost Attack against the hCaptcha System

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Hash tables are an essential data-structure for numerous networking applications (e.g., connection tracking, firewalls, network address translators). Among these, cuckoo hash tables provide excellent performance by allowing lookups to be…

Networking and Internet Architecture · Computer Science 2017-12-29 Nicolas Le Scouarnec

Crowdsourcing human-solving or online typing attacks are destructive problems. However, studies into these topics have been limited. In this paper, we focus on this kind of attacks whereby all the CAPTCHAs can be simply broken because of…

Cryptography and Security · Computer Science 2019-04-30 Jianyi Zhang , Xiali Hei , Zhiqiang Wang

Online services rely on CAPTCHAs as a first line of defense against automated abuse, yet recent advances in multi-modal large language models (MLLMs) have eroded the effectiveness of conventional designs that focus on text recognition or 2D…

Artificial Intelligence · Computer Science 2025-10-07 Arina Kharlamova , Bowei He , Chen Ma , Xue Liu

Preventing abusive activities caused by adversaries accessing online services at a rate exceeding that expected by websites has become an ever-increasing problem. CAPTCHAs and SMS authentication are widely used to provide a solution by…

Cryptography and Security · Computer Science 2024-06-27 Kosei Akama , Yoshimichi Nakatsuka , Masaaki Sato , Keisuke Uehara

As autonomous AI agents increasingly populate the Internet, a novel security challenge arises: "Is this entity an AI agent?" It is a new entity-type verification problem with no established solution. We formalize the problem through a…

Cryptography and Security · Computer Science 2026-03-10 Zuyao Xu , Xiang Li , Fubin Wu , Yuqi Qiu , Lu Sun , FaSheng Miao

Image captioning models are encoder-decoder architectures trained on large-scale image-text datasets, making them susceptible to adversarial attacks. We present CaptionFool, a novel universal (input-agnostic) adversarial attack against…

Computer Vision and Pattern Recognition · Computer Science 2026-03-03 Swapnil Parekh

Adversarial patches pose a realistic threat model for physical world attacks on autonomous systems via their perception component. Autonomous systems in safety-critical domains such as automated driving should thus contain a fail-safe…

Machine Learning · Computer Science 2021-02-09 Jan Hendrik Metzen , Maksym Yatsura

We present a new hardware-agnostic side-channel attack that targets one of the most fundamental software caches in modern computer systems: the operating system page cache. The page cache is a pure software cache that contains all…

Cryptography and Security · Computer Science 2019-01-07 Daniel Gruss , Erik Kraft , Trishita Tiwari , Michael Schwarz , Ari Trachtenberg , Jason Hennessey , Alex Ionescu , Anders Fogh

Traditional CAPTCHA (Completely Automated Public Turing Test to Tell Computers and Humans Apart) schemes are increasingly vulnerable to automated attacks powered by deep neural networks (DNNs). Existing adversarial attack methods often rely…

Computer Vision and Pattern Recognition · Computer Science 2025-07-02 Xia Du , Xiaoyuan Liu , Jizhe Zhou , Zheng Lin , Chi-man Pun , Cong Wu , Tao Li , Zhe Chen , Wei Ni , Jun Luo

CAPTCHAs are widely deployed as human verification mechanisms and frequently block intelligent agents from completing end-to-end automation in real-world web environments. Solving modern CAPTCHAs requires robust multi-step visual reasoning…

Computer Vision and Pattern Recognition · Computer Science 2026-05-20 Pengcheng Wang , Haoxiang Liu , Yang Dai , Xiangxiang Zeng , Guanhua Chen , Baotian Hu , Longyue Wang , Weihua Luo

We propose a new scheme of attack on the Microsoft's ASIRRA CAPTCHA which represents a significant shortcut to the intended attacking path, as it is not based in any advance in the state of the art on the field of image recognition. After…

Cryptography and Security · Computer Science 2009-08-11 Carlos Javier Hernandez-Castro , Arturo Ribagorda , Yago Saez

We introduce the Context Compliance Attack (CCA), a novel, optimization-free method for bypassing AI safety mechanisms. Unlike current approaches -- which rely on complex prompt engineering and computationally intensive optimization -- CCA…

Cryptography and Security · Computer Science 2025-03-10 Mark Russinovich , Ahmed Salem

Automated bots now account for roughly half of all web requests, and an increasing number deliberately spoof their identity to either evade detection or to not respect robots.txt. Existing countermeasures are either resource-intensive…

Networking and Internet Architecture · Computer Science 2026-04-01 Rémi Van Boxem , Tom Barbette , Cristel Pelsser , Ramin Sadre

Ensuring the security of computers is a non-trivial task, with many techniques used by malicious users to compromise these systems. In recent years a new threat has emerged in the form of networks of hijacked zombie machines used to perform…

Artificial Intelligence · Computer Science 2016-11-18 Yousof Al-Hammadi , Uwe Aickelin , Julie Greensmith

We propose an intriguingly simple method for the construction of adversarial images in the black-box setting. In constrast to the white-box scenario, constructing black-box adversarial images has the additional constraint on query budget,…

Machine Learning · Computer Science 2019-08-16 Chuan Guo , Jacob R. Gardner , Yurong You , Andrew Gordon Wilson , Kilian Q. Weinberger

Modern CAPTCHAs rely heavily on vision tasks that are supposedly hard for computers but easy for humans. However, advances in image recognition models pose a significant threat to such CAPTCHAs. These models can easily be fooled by…

Computer Vision and Pattern Recognition · Computer Science 2024-09-10 Yahya Jabary , Andreas Plesner , Turlan Kuzhagaliyev , Roger Wattenhofer

Turing test was originally proposed to examine whether machine's behavior is indistinguishable from a human. The most popular and practical Turing test is CAPTCHA, which is to discriminate algorithm from human by offering recognition-alike…

Computer Vision and Pattern Recognition · Computer Science 2019-04-23 Jiaming Zhang , Jitao Sang , Kaiyuan Xu , Shangxi Wu , Yongli Hu , Yanfeng Sun , Jian Yu

To mitigate dictionary attacks or similar undesirable automated attacks to information systems, developers mostly prefer using CAPTCHA challenges as Human Interactive Proofs (HIPs) to distinguish between human users and scripts. Appropriate…

Cryptography and Security · Computer Science 2023-12-01 Emre Mulazimoglu , Murat P. Cakir , Cengiz Acarturk

The advancements in generative AI have enabled the improvement of audio synthesis models, including text-to-speech and voice conversion. This raises concerns about its potential misuse in social manipulation and political interference, as…

Cryptography and Security · Computer Science 2024-09-12 Hong-Hanh Nguyen-Le , Van-Tuan Tran , Dinh-Thuc Nguyen , Nhien-An Le-Khac

CPU caches introduce variations into the execution time of programs that can be exploited by adversaries to recover private information about users or cryptographic keys. Establishing the security of countermeasures against this threat…

Cryptography and Security · Computer Science 2017-05-12 Goran Doychev , Boris Köpf