Survey on usable and secure two-factor authentication

System resources are usually not retrieved through deception by users who are not legal. This is basically ensured by Authentication. Text password is one of the forms of user authentication that is very suitable due to its ease and convenience. However such passwords are prone to be stolen and negotiated under different threats and vulnerabilities. Users often select weak passwords and tend to use the same password across different websites. Users are required to remember more, longer and changing passwords. An adversary can launch several passwords stealing attacks and gain access to user's personal data. It is evident that a convenient and more secure form of user authentication is necessary. The authentication mechanism called Two-factor authentication is introduced to overcome this drawback. Two factors compared to one factor generally deliver a higher level of security assurance. Various schemes have been proposed which allow the users to freely choose their password like PassFile, and thus eliminate the problem of entering and remembering the reusable password. These schemes use a smart card and are secure against various possible attacks.