SeongHan Shin Kazukuni Kobara Hideki Imai A Secure Authenticated Key Exchange Protocol for Credential Services. 139-149 2008 91-A IEICE Transactions 1 http://dx.doi.org/10.1093/ietfec/e91-a.1.139 db/journals/ieicet/ieicet91a.html#ShinKI08