CARSI (CERNET Authentication and Resource Sharing Infrastructure), is an inter-institutional authentication and authorization service initiated by Peking University and aimed at Chinese universities, colleges, schools and research institutes. CARSI focuses on building an authentication and authorization infrastructure for CERNET educational institutions and users so that web resources developed by universities or deployed on internet can be visited by university faculty and students easily. The corner stone for this cross-domain authentication and authorization infrastructure is the campus-wide identity management systems which are daily online services in most Chinese universities.