Identity Management System

iii Passwords are the most common form of user authentication today. When passwords were first introduced in the 1960s, computers were a scarce resource, and experts had at most a few passwords to manage. However, today, we are surrounded by many computers and services, and passwords are imposing a growing burden on users. As a way of coping, users choose insecure behaviors, such as writing down passwords, choosing weak passwords, or reusing passwords for multiple accounts. One result is that passwords are now a major source of vulnerabilities in computer systems. To address this problem, I designed, implemented and evaluated the Unified Authentication Framework (UniAuth in short). The three core ideas behind UniAuth are 1) a user will have one smart device that manages all of their credentials, 2) the smart device can communicate with online services as well as physical devices via a standardized protocol to handle activities related to user authentication (such a