Recognition of text CAPTCHA by using back propagation algorithm of artificial neural network

Abstract

Text-based CAPTCHA is a very simple type of CAPTCHA which are most widely used. It uses only a group of characters. In this paper, we focus on how Text based CAPTCHA is recognized by machine learning techniques. This paper proposed a method based on Back Propagation algorithm to identify the Text based CAPTCHA. The proposed technique improves the security level of Text-based CAPTCHA storage system by using the Back-propagation method of Artificial Neural Network. We used NNToolbox to train the network in MATLAB software.