Boosting the transferability of adversarial CAPTCHAs

Zisheng Xu, Qiao Yan

Abstract: Highlights•We emphasize the importance of improving the transferability of adversarial CAPTCHAs, as it has not been discussed before.•We propose CFA, a method for generating more transferable adversarial CAPTCHAs by altering the robust content features in the original CAPTCHA.•We propose weighted gradient aggregation based on the confidence in the selection process in CFA, which can further enhance the performance of the adversarial CAPTCHAs.