Make complex CAPTCHAs simple: A fast text captcha solver based on a small number of samples

Yao Wang, Yuliang Wei, Mingjin Zhang, Yang Liu, Bailing Wang

Abstract: Highlights•A captcha transformation model is proposed to simplify complex captchas.•Cycle generative adversarial networks are used to construct the model.•Only a small amount of labeled data is required to achieve high attack rates.•A simple neural network is designed to speed up the recognition process.