Machine Learning Paradigm for Internet of Things Applications

5Generation of Two-Dimensional Text-Based CAPTCHA Using Graphical Operation

S. Pradeep Kumar* and G. Kalpana

Dept. of CSE, Saveetha School of Engineering, Saveetha Nagar, Thandalam, Chennai, India

Abstract

Text-based CAPTCHA is used as a standard security method to prevent the websites from bots and phishing attacks. However, nowadays, hackers are writing a false program to break the text-based CAPTCHA scheme due to their poor strength. In the proposed two-dimensional text-based CAPTCHA approach, the number of characters is dynamic, i.e., changes with every attempt, and all the characters are tilted and rotated in some specific angle, using graphical operation. To further intensify the security, the characters will collide with each other forming a parabolic shape and each will be of different sizes and colors, creating multiple permutations and combinations of size and pixel intensity. The resultant CAPTCHA thus generated is highly secure and can be used in sensitive applications such as defense, inventory management, social media, and banking services.

Keywords: Web security, graphical operation

5.1 Introduction

In the year 2000, researchers from Carnegie Mellon University designed a text-based CAPTCHA approach to restrict attackers entering the Yahoo Chat Rooms [1]. CAPTCHA, Completely Automated Public Turing Test to Tell Computers and Humans Apart [2], are also called as a Reverse Turing Test; subsequently, they were and are envisioned to enable a computer to determine ...