Capacitive Touchscreens at Risk: A Practical Side-Channel Attack on Smartphones via Electromagnetic Emanations

Fuente: arXiv
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Autores principales: Cheng, Yukun, Ou, Changhai, Zhu, Shiyu, Zhang, Jinyuan, Qiu, Zhenfang, Han, Xingshuo, Zhang, Tianwei, Li, Yuan, Zheng, Shihui
Formato: Preprint
Publicado: 2026
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author Cheng, Yukun
Ou, Changhai
Zhu, Shiyu
Zhang, Jinyuan
Qiu, Zhenfang
Han, Xingshuo
Zhang, Tianwei
Li, Yuan
Zheng, Shihui
author_facet Cheng, Yukun
Ou, Changhai
Zhu, Shiyu
Zhang, Jinyuan
Qiu, Zhenfang
Han, Xingshuo
Zhang, Tianwei
Li, Yuan
Zheng, Shihui
contents Capacitive touchscreens in modern smartphones introduce severe side-channel vulnerabilities. However, existing attacks often require restrictive conditions or invasive measurements. This paper presents TESLA, a novel, contactless electromagnetic (EM) side-channel attack that exploits inherent EM emanations during touchscreen scanning. We demonstrate that these emanations encode the spatiotemporal evolution of touch interactions, forming a unified leakage basis. By secretly placing an EM probe near the victim's device, TESLA enables attackers to extract highly sensitive information, including screen-unlocking PIN codes, keyboard inputs, interacting application categories, and continuous handwriting trajectories. Compared to existing attacks, TESLA offers a broader range of attack targets, more efficient sample acquisition, and operations in practical attack scenarios. Extensive evaluations on popular commercial smartphones, specifically the iPhone X, Xiaomi 10 Pro, Samsung S10, and Huawei Mate 30 Pro, validate the effectiveness of TESLA. It achieves remarkable inference accuracy in diverse settings such as private meeting rooms and public libraries, with success rates of 99.3% for PIN code recognition, 97.6% for keyboard input reconstruction, and 95.0% for application inference, respectively. Simultaneously, it attains a 76.8% character recognition accuracy and a high geometric similarity (Jaccard index of 0.74) for 2D handwriting trajectory reconstruction.
format Preprint
id arxiv_https___arxiv_org_abs_2605_14633
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Capacitive Touchscreens at Risk: A Practical Side-Channel Attack on Smartphones via Electromagnetic Emanations
Cheng, Yukun
Ou, Changhai
Zhu, Shiyu
Zhang, Jinyuan
Qiu, Zhenfang
Han, Xingshuo
Zhang, Tianwei
Li, Yuan
Zheng, Shihui
Cryptography and Security
Capacitive touchscreens in modern smartphones introduce severe side-channel vulnerabilities. However, existing attacks often require restrictive conditions or invasive measurements. This paper presents TESLA, a novel, contactless electromagnetic (EM) side-channel attack that exploits inherent EM emanations during touchscreen scanning. We demonstrate that these emanations encode the spatiotemporal evolution of touch interactions, forming a unified leakage basis. By secretly placing an EM probe near the victim's device, TESLA enables attackers to extract highly sensitive information, including screen-unlocking PIN codes, keyboard inputs, interacting application categories, and continuous handwriting trajectories. Compared to existing attacks, TESLA offers a broader range of attack targets, more efficient sample acquisition, and operations in practical attack scenarios. Extensive evaluations on popular commercial smartphones, specifically the iPhone X, Xiaomi 10 Pro, Samsung S10, and Huawei Mate 30 Pro, validate the effectiveness of TESLA. It achieves remarkable inference accuracy in diverse settings such as private meeting rooms and public libraries, with success rates of 99.3% for PIN code recognition, 97.6% for keyboard input reconstruction, and 95.0% for application inference, respectively. Simultaneously, it attains a 76.8% character recognition accuracy and a high geometric similarity (Jaccard index of 0.74) for 2D handwriting trajectory reconstruction.
title Capacitive Touchscreens at Risk: A Practical Side-Channel Attack on Smartphones via Electromagnetic Emanations
topic Cryptography and Security
url https://arxiv.org/abs/2605.14633