Date Added: Oct 2009
User authentication is one of the important topics in information security. Text-based strong password scheme can provide security to a certain degree. However, the fact that strong passwords being difficult to memorize often leads their owners to write them down on papers or even save them in a computer file. Graphical authentication has been proposed as a possible alternative solution to text-based authentication, motivated particularly by the fact that humans can remember images better than text. Recently, many networks, computer system and Internet-based environments try using graphical authentication techniques as their user's authentication. Graphical passwords have two essential aspects, usability and security.