Research output: Book/Report/Proceedings › Other report
Research output: Book/Report/Proceedings › Other report
}
TY - BOOK
T1 - The Robustness of Google CAPTCHAs
AU - El Ahmad, A.S.
AU - Yan, Jeff
AU - Tayara, Mohamad
PY - 2011/9
Y1 - 2011/9
N2 - We report a novel attack on two CAPTCHAs that have been widely deployed on the Internet, one being Google's home design and the other acquired by Google (i.e. reCAPTCHA). With a minor change, our attack program also works well on the latest ReCAPTCHA version, which uses a new defence mechanism that was unknown to us when we designed our attack. This suggests that our attack works in a fundamental level. Our attack appears to be applicable to a whole family of text CAPTCHAs that build on top of the popular segmentation-resistant mechanism of "crowding character together" for security. Next, we propose a novel framework that guides the application of our well-tested security engineering methodology for evaluating CAPTCHA robustness, and we propose a new general principle for CAPTCHA design.
AB - We report a novel attack on two CAPTCHAs that have been widely deployed on the Internet, one being Google's home design and the other acquired by Google (i.e. reCAPTCHA). With a minor change, our attack program also works well on the latest ReCAPTCHA version, which uses a new defence mechanism that was unknown to us when we designed our attack. This suggests that our attack works in a fundamental level. Our attack appears to be applicable to a whole family of text CAPTCHAs that build on top of the popular segmentation-resistant mechanism of "crowding character together" for security. Next, we propose a novel framework that guides the application of our well-tested security engineering methodology for evaluating CAPTCHA robustness, and we propose a new general principle for CAPTCHA design.
KW - captcha
KW - robustness
KW - segmentation attack
M3 - Other report
T3 - School of Computing Science Technical Report Series
BT - The Robustness of Google CAPTCHAs
PB - Newcastle University School of Computing Science
CY - Newcastle Upon Tyne
ER -