Comparative Analysis and Framework Evaluating Web Single Sign-On Systems FURKAN ALACA, School of Computing, Queen’s University,
[email protected] PAUL C. VAN OORSCHOT, School of Computer Science, Carleton University,
[email protected] We perform a comprehensive analysis and comparison of 14 web single sign-on (SSO) systems proposed and/or deployed over the last decade, including federated identity and credential/password management schemes. We identify common design properties and use them to develop a taxonomy for SSO schemes, highlighting the associated trade-offs in benefits (positive attributes) offered. We develop a framework to evaluate the schemes, in which weidentify14 security, usability, deployability, and privacy benefits. We also discuss how differences in priorities between users, service providers (SPs), and identity providers (IdPs) impact the design and deployment of SSO schemes. 1 INTRODUCTION Password-based authentication has numerous documented drawbacks. Despite the many password alternatives, no scheme has thus far offered improved security without trading off deployability or usability [8]. Single Sign-On (SSO) systems have the potential to strengthen web authentication while largely retaining the benefits of conventional password-based authentication. We analyze in depth the state-of-the art ofwebSSO through the lens of usability, deployability, security, and privacy, to construct a taxonomy and evaluation framework based on different SSO architecture design properties and their associated benefits and drawbacks. SSO is an umbrella term for schemes that allow users to rely on a single master credential to access a multitude of online accounts. We categorize SSO schemes across two broad categories: federated identity systems (FIS) and credential managers (CM).