Design of single sign-on

As IT systems proliferate to support business processes, users typically have to sign-on to multiple systems, necessitating an equivalent number of sign-on dialogues. Single sign-on can resolve the problem well. We first introduce the situation which makes the SSO becomes necessary. Then we elaborate the first version of our system and analyze its problems. Next, we improve the first version and propose the second version. Finally, we analyse the system and acknowledge the problems left open