부산대학교 도서관

A method (200) of operation in a mobile communication system (100) includes: a mobile station (101) sending (207) to a visited network (103) a certified service record, provided by a home network (102), of communication services allowed to be provided to the mobile station, the service record being accompanied by or including a certificate code applied by the home network by a calculation procedure applied to contents of the service record using an authentication key; the visited network calculating (211) an authentication code for the service record using an authentication key obtained by the visited network; the visited network authenticating (212) the service record by matching (212) the certificate and authentication codes; and the visited network providing (215) communication services to the mobile station based upon the authenticated service record.