Combining the use of tokens and policy agents, the problem of Single Sign On (SSO) among platforms and applications, especially SSO among cross-domains, could be solved.

• 为实现用户在平台和应用系统之间的单点登录，提出了令牌和代理相结合进行身份信息传递与验证的实现方案，尤其是解决了跨域单点登录的难题。