The main objective of the research is to propose the effective methods of using two-dimensional n�n passwords in terms of providing secure authentication to inactive users of the system during vulnerable state. The proposition is based on the fact that if the system goes in to unsafe state due to some intrusion threat then to make the system available to the end user, it is required by the users to re-authenticate using special mechanism. These users can become active once authenticated and can continue their tasks using alternate services. These n�n passwords are long and complex, hence are difficult to memorize. But these can be very useful in certain alarming situations such as in case of system being under threat. Proposed methods provide the maximum benefits in terms of secure authentication to the system resources that is under threat. Three methods have been proposed that are classified on the way the password is created or generated. The strength and limitations of all the proposed methods has also been analyzed. © 2011 Asian Network for Scientific Information.