In this paper, based on CORBA security service specification [14], we propose the open authentication model for electronic commerce with an extension to the Kerberos authentication framework using public key cryptosystem. This proposed structure, by Kerberos [Kohl, Neuman and Ts'o, 9] for the authentication of peer entities, assures not only the identification of peer entities and the confidence of origin of business item for negotiations. Since our deployed Kerberos is extended to the PKC [Sirbu and Chung-I Chuang, 20] systems in distributed computing, it provides the flexibility of key management and the ability to leverage the certification infrastructure.