Meanwhile, user behavior has played a crucial role in system security especially in authentication area. Typically, authentication is achieved by account and access password verification, token such as access card identification, or biometrics which is referred to user's body parts. However, those approaches are not effective and efficiency enough as password will lose their effectiveness once they are compromised; token can be stolen or lost; while biometrics requires high installation cost. Moreover, once authentication occurs, there is no guarantee that the initial authentic user is still the same person. As a result, the system security is strengthened by incorporate continuous authentication during session monitoring the user behavior. If the behavior is found to be anomaly, re-authentication process is performed immediately. At system level, user behavior is also useful for intrusion detection. An intrusion can be identified before it happens based on some specific behavioral patterns indicating of suspicious identities or actions.

Theoretical Perspectives

As mentioned earlier, computer system is built for user but not vice versa. Thus, the computer system should behave as user expected and required. In order to understand the user, his or her behavior on using the system must be known. The following were some of the common user behaviors: (12)

User doesn't like to wait.

User prefers some entertained graphical elements like animation.

User doesn't like to repeat the same tasks.

User hates repetitive confirmation and information.

However, different user may have different behaviors and preferences. Therefore, the system needs to identify the user behavior and keep track on it from time to time because the user behavior may be changed along the way. In this case, observation on user behavior which typically based on log files is needed and