计算机工程与应用 ›› 2012, Vol. 48 ›› Issue (6): 196-199.

• 图形、图像、模式识别 • 上一篇    下一篇

覆盖约简算法在Captcha识别方面的应用

贾瑞玉1,李永顺 1,倪志伟2   

  1. 1.安徽大学 计算机科学与技术学院,合肥 230039
    2.合肥工业大学 智能管理研究所,合肥 230009
  • 收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:2012-02-21 发布日期:2012-02-21

Application of reducing covering algorithm in Captcha attack

JIA Ruiyu1, LI Yongshun1, NI Zhiwei2   

  1. 1.School of Computer Science and Technology, Anhui University, Hefei 230039, China
    2.Institute of Intelligent Management, Hefei University of Technology, Hefei 230009, China
  • Received:1900-01-01 Revised:1900-01-01 Online:2012-02-21 Published:2012-02-21

摘要: Captcha是用来区分计算机与人类的一种程序,图像验证码是一种典型的Captcha。对图像验证码的发展历程进行了总结,比较了几种目前最常见验证码的特点和设计思路,提出了对一般验证码的破解方法,并设计实现了提取验证码数据的图片信息提取系统;应用基于条件信息熵的覆盖约简算法,对验证码进行识别,对比实验结果证明,识别效果良好。

Abstract: Captcha is a program which can be used to distinguish between computer and human, the image verification code is a typical application of Captcha. The development of the Captcha is summarized, and the feature and design ideas of the common Captcha are also compared. Then this paper presents the attack method on common Captcha and designs the system of feature extraction of Captcha, reducing covering algorithm based on conditional information entropy is designed and applied to attack Captcha. The experimental results prove that the model achieve excellent robust and high success recognition rate.