CAPTCHA-Based Image Steganography to Achieve User Authentication

Abstract

In recent days, steganography is the major promising data hiding technique. Data can be hidden by different techniques. Similarly, attackers also develop many tools to break the technique and retrieve the data. In recent trends, CAPTCHA is introduced to ensure that the receiver is a human being and not a robot. To authenticate the user and to increase the confidentiality, a randomized CAPTCHA code is created. Steganography is the method and to hide the secret data from an unauthorized access. The steganography method tends to mute the visibility of the secret data into a cover file of different multimedia type. Passing of a secret message over a medium in modern days, the newly invented steganography techniques are used to embed the data into the original cover image. To achieve secret and reliable data communication, the encryption and decryption mechanism is used. A predefined procedure cannot be detectable by the system. After establishing a secure connection between an authenticate sender and receiver, the original secret message is transmitted using image steganography algorithm. Our proposed algorithm gives the better PSNR ratio (~1.04%) compared with the existing method and also minimizes the MSE.