User authentication is necessary to secure the data and process on internet or mobile communications. Most commonly employed system for said purpose is Static alpha-numeric password based authentication system. But they are susceptible to various types of active and passive attacks. One of the promising alternatives is Graphical password based authentication systems which if implemented properly are secure but not as easy to understand or learn.
In this paper we propose a varied version of inkblot authentication  graphical password system which is secure as well as usable. It generates pseudo random one time passwords using a set of inkblots unique to the user. Properties of one time passwords ensures the resistance towards replay, phishing, shoulder surfing, active and dictionary attacks. We also analyze the results from two experiments we have conducted to confirm that this system is easy to learn and password memorability is high, thus making it a promising authentication mechanism.