Keystroke Biometric: Background

We have been exploring keystroke biometric applications. Keystroke biometric systems measure typing characteristics believed to be unique to an individual and difficult to duplicate. There are two commercial products currently used for hardening passwords (short input) in existing computer security schemes. The keystroke biometric is one of the less-studied biometrics; researchers tend to collect their own data and no known studies have compared identification techniques on a common database. Nevertheless, the published literature is optimistic about the potential of keystroke dynamics to benefit computer system security and usability.

The keystroke biometric has several possible applications. One application is to identify an individual from his/her keystroke pattern (one-of-n response). Suppose, for example, there has been a problem with the circulation of offensive emails from easily accessible desktops in a work environment. The security department wants to reduce this problem by collecting keystroke biometric data from all employees and developing a keystroke biometric identification system.

A second application is an authentication process (binary accept/reject response, yes you are the person you claim to be or no you are not). For example, password entry could be "hardened" by adding as a keystroke authentication process as a second stage following password matching before allowing user entry. Thus, if the password is not entered in the normal keystroke pattern, the system could ask the user to reenter it. For example, a user on a particular occasion might be drinking a cup of coffee and be entering the password uncharacteristically with one hand. The system, then, could reject the password, sending the user a message like, "Please reenter your password in your normal manner," and after, say, three tries, possibly rejecting the user entirely. The user upon receiving the message would likely put down the coffee cup and enter the password in his/her normal fashion in order to be accepted. Another use of such an authentication process is to authenticate students taking online tests by their keystroke patterns.

Over the last six years, we have developed in CSIS at Pace University keystroke biometric systems for identification (one-of-n response) and for authentication (accept/reject response). We have presented experimental results at several internal conferences, at three external conferences, and have recently had a book chapter and a technical report published. The book chapter and technical report (see references below) should be read carefully to obtain an understanding of our system. Following recent work we will focus this semester on the authentication application of verifying the identity of students taking online tests.