Netinfo Security ›› 2022, Vol. 22 ›› Issue (10): 129-135.doi: 10.3969/j.issn.1671-1122.2022.10.018

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CAPTCHA Security Enhancement Method Incorporating Multiple Style Migration and Adversarial Examples

ZHANG Zhi, LI Xin(), YE Naifu, HU Kaixi   

  1. School of Information Network Security, People’s Public Security University of China, Beijing 100038, China
  • Received:2022-07-03 Online:2022-10-10 Published:2022-11-15
  • Contact: LI Xin E-mail:lixin@ppsuc.edu.cn

Abstract:

Completely automated public turing test to tell computers and humans apart(CAPTCHA) plays an important role in preventing automated attacks against Web services, but it is difficult to provide effective security protection when facing cracking tools with automatic recognition technology. If highly distorted and other brute force methods are used, it is difficult to recognize even by human eyes. This paper proposed a CAPTCHA security enhancement method incorporating multiple style migration and adversarial examples to defend unknown machine recognition by multiple style transfer while preserving the original content, and added noise to attack common models by adversarial examples to deceive neural networks. Experimental results on the text CAPTCHA dataset show that the generation algorithm proposed in this paper has a lower machine recognition rate and effectively improves the security of text CAPTCHA.

Key words: CAPTCHA, deep learning, image style transfer, adversarial examples, convolutional neural network

CLC Number: