1st TIPPI Workshop

Trustworthy Interfaces for Passwords and Personal Information

Speaker: Rachna Dhamija, U.C. Berkeley

Title: Trustworthy User Interface Design: Dynamic Security Skins

We propose a new scheme, Dynamic Security Skins, that allows a remote web server to prove its identity in a way that is easy for a human user to verify and hard for an attacker to spoof. We present two novel interaction techniques to prevent spoofing. First, we provide a trusted window in the web browser that is dedicated to username and password entry. We use a photographic image to create a trusted path between the user and this window to prevent spoofing of the window and of the text entry fields. Second, our scheme allows the remote server to generate a unique abstract image for each user and each transaction. This image creates a ~Sskin~T that automatically customizes the browser window or the user interface elements in the content of a remote web page. Our extension allows the user~Rs browser to independently compute the image that it expects to receive from the server. To authenticate content from the server, the user can visually verify that the images match.

In contrast to other proposals, our scheme places a very low burden on the user in terms of effort, memory and time. To authenticate himself, the user has to recognize only one image and remember one low entropy password, no matter how many servers he wishes to interact with. To authenticate content from an authenticated server, the user only needs to perform one visual matching operation to compare two images. Furthermore, it places a high burden of effort on an attacker to spoof customized security indicators.

Rachna Dhamija is a Ph.D. candidate at the School of Information Management and Systems at U.C. Berkeley. Her research spans the fields of computer security and human computer interaction, and her dissertation focuses on the design and evaluation of usable systems for user and server authentication. Before coming to Berkeley, she worked on electronic commerce privacy and security at CyberCash.

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