A New Security Primitive Based on Hard AI Problems and Efficient User Authentication using Captcha and Graphical Passwords Journal title: International Journal of Innovative Research in Computer Science and Technology Authors: Bhagyashri A. Banarase, Prof. Meghali A. kalyankar Subject(s): Electrical and Electronic Engineering, Chemical Engineering, Civil Engineering, Computer Science, Artificial Intelligence, Computer Science, Information Systems, Computer Science, Interdisciplinary Applications, Engineering, Multidisciplinary, Engineering, Civil, Computer Science, Cybernetics, Computer Science, Theory & Methods, Computer Science, Software Engineering