SAML-based single sign-on for legacy system

The Single Sign-On is used for users to solve the logging in and the passwords managing problems in different application systems. However, the traditional SSO system cannot provide an appropriate solution for legacy systems which are independent and hardly modifiable. In order to solve the problem, we present a new SSO method based on the SAML legacy System. In this paper, the structure of the new method is given, the communication protocol between users and identity provider is defined, and the security of the method is analyzed. This method inserts the identity provider between systems and users without modifying them, authenticates the users by the SAML token, and implements the SSO in different application servers systems by auto form filling.