Candidate: Newman Fabian Monrose
Advisor: Zvi Kedem

Towards Stronger User Authentication
11 a.m., April 27, 1999
7th floor conference room, 715 Broadway


Password-based authentication is the dominant mechanism for verifying the identity of computer users, even though it is well known that people frequently choose passwords that are vulnerable to dictionary attacks. This talk addresses the issue of improving the security of password-based authentication, and presents authentication techniques that are more secure than traditional approaches against both on-line and off-line attacks.

We present a technique for strengthening the security of a textual password by augmenting it with biometric information such as the duration and latency of keystrokes during entry of the password. Thereby, both the password and the user's typing pattern are used to corroborate the user's identity. The technique presented adapts to gradual changes in a user's typing pattern while maintaining the same strengthened password across authenticated sessions. Moreover, our technique does not reveal which of a user's keystroke features are used to generate the corresponding strengthened password. This knowledge is hidden even from an attacker who captures all the system information used by the authentication server, and we show that our technique increases significantly the amount of work such an attacker must perform.

Additionally, we present an alternative technique for user authentication that exploits features of graphical input devices. We propose and evaluate ``graphical passwords'', which serve the same purpose as textual passwords, but consist of handwritten drawings, possibly in addition to text. Graphical passwords derive their strength from the fact that graphical input devices allow one to decouple the positions of inputs from the temporal order in which these inputs occur. We use this independence to build new password-based authentication schemes that are convincingly stronger than conventional methods.