Antiphishing Using Dynamic Image Captcha Based On (t, n) VCS

Abstract: Due to the evolution of new technologies in the world of internet,E-commerce has become a very common and there are various attacks present behind this, one of them is phishing. Phishing is an attempt to retrieve personal and confidential information such as username, banking password, credit card details and account number etc.of users. In this project we have proposing a new technique named as “Antiphishing using dynamic image captcha based on (t, n) VCS”. The (t, n) VCS is secret sharing scheme where original image captcha is encoded into n shares (transparencies), and the stacking of any t out of n shares (transparencies) revels the secret image. The stacking of t-1 or fewer shares(transparencies) is unable to extract any information about the secret. To reduce the overhead of generatingn shares (transparencies) of user, this project proposes dynamic image captcha authentication using (t, n) VCS with unlimited n based on (t, n) VCS algorithm. Here original image captcha is divided into n number of shares, where one share stores with user and the remaining shares store in server. User’s share is stacked with servers share to reveal the secret image for identifying phishing website; theindividual sheet images do not reveal the secret image. Here users need to remember original image captcha for decryption. In this project we used (t, n) VCS based on basis matrices and the probabilistic model where optimal contrast with t=2 to 6 and n=2 to 10 are solved in this project.

Keywords: DynamicImage Captcha, Phishing, Secret Sharing, Visual Cryptography Scheme (VCS).