关键词: 验证码, 特征识别, 颜色填充, 三线条法, 全面扫描

Abstract:

This paper introduces a method for breaking the text-based image CAPTCHA based on feature recognition.It also describes the procedures of breaking SPD Bank CAPTCHA in details:preprocessing,extraction,and recognition.In the recognition phase,we propose three feature-based recognition methods for SPD Bank:color-filling,three-lines and full scan.The success rate and the speed of the results are desirable.The experiments show that our attack achieves a success rate of as high as 78%.Both the feature recognition method and the crack method are also applicable to other non-adhesion of the text-based CAPTCHA.

Key words: CAPTCHA;feature recognition;color-filling;three-line;full scan